Time to Teach: Instructional Time and Science Teachers’ Use of Inquiry-Oriented Instructional Practices

Conclusions: Identifying optimal allocations of instructional time is a relevant consideration in efforts to promote the types of reform-oriented science teaching called for by the National Research Council’s Framework for K–12 Science Education, the Next Generation Science Standards (NGSS), and other national and state science assessments. Although investments in teacher training and professional development are also necessary and important investments, with insufficient time, even the most qualified or best trained science teachers may struggle to use inquiry-based instructional approaches.

Science and education professionals have repeatedly called for more widespread use of inquiry-oriented science instruction in schools (Duschl et al., 2007; National Research Council, 1996, 2012). This type of teaching emphasizes learning science concepts and skills through sustained real-world projects and experimentation, and deemphasizes fact memorization, recall, and executing prescribed experiments (National Research Council, 2012). The push to reform K–12 science instruction is based on research suggesting that teaching and learning grounded in scientific inquiry improves student interest and achievement in science (Schroeder et al., 2007).

Multiple efforts have been made to encourage inquiry-oriented science instruction in schools, including the National Research Council’s Framework for K–12 Science Education and, more recently, the Next Generation Science Standards (NGSS) and the National Assessment of Educational Progress’ (NAEP’s) science assessments. All call for a greater emphasis on scientific investigation and inquiry in K12 science education. Yet, despite external pressure and, in some instances, incentives to reform science teaching, there are long-standing concerns with the pace at which frameworks and instructional approaches that support inquiry-based science teaching have been adopted (National Academies of Sciences, Engineering, & Medicine, 2015). This is especially the case for changes to science instruction at the elementary and middle grades (McEwin & Greene, 2011). As efforts to reform science education press forward, policy makers and educators need to understand the conditions that constrain and promote inquiry-oriented science instruction.

This study focuses on one aspect of organizational context that may influence teachers’ use of inquiry-oriented science instruction: the amount of time available to teach science. Inquiry-oriented instructional practices involve cognitively complex tasks that require sufficient time for teachers to prepare instruction and for students to engage in learning activities (Barron et al., 1998; Geier et al., 2008), and nascent research evidence suggests that time may impact teachers’ capacity to engage in reform-oriented science teaching (Traphagen et al., 2011).

There have also been growing concerns about the amount of time spent on elementary- and middle-level science instruction. On average, students spend less time on science than they do in other core subject areas, and in the wake of the federal No Child Left Behind legislation’s accountability provisions, many schools reduced the amount of time available for science education (Blank, 2013; Judson, 2013; Morton & Dalton, 2007). For instance, since 2001, time for science instruction in grades K–8 dropped to 2.3 hours per week, the lowest level since 1988 and an almost 23% decline from the 1993–1994 school year (Blank, 2013). These circumstances have led science education advocates to question whether the amount of time available in school schedules is sufficient to support effective inquiry-based teaching and learning (Marx & Harris, 2006; Shields et al., 2011; Traphagen & Johnson-Staub, 2010).

Although arguments for more instructional time for science may be intuitively appealing, little empirical evidence supports or refutes claims that the amount of time available for science instruction impacts instructional practice. Furthermore, decision makers must also weigh investments in instructional time in light of those made in other instructional resources. Other school resources, particularly teacher qualifications and investments in teacher professional development, may also impact the extent to which inquiry-oriented science instruction occurs in the classroom (Kolbe & Jorgenson, 2018; Smith et al., 2007).

In this study, we used data from the NAEP’s 2011 Grade 8 Science Assessment to examine whether amount of time available for science instruction is associated with middle-level science teachers’ use of inquiry-oriented instructional practices. Additionally, we explored the extent to which other instructional resources—namely, qualified teachers and teacher professional development—influence the relationship between time and teachers’ instructional practice. Instructional time and teacher qualifications are key policy-malleable resources. Taken together, time, teacher qualifications, and teacher professional development represent the bulk of most school budgets. Identifying optimal allocations of time and investments in teacher qualifications and training holds potential for helping decision makers identify more and less effective options for improving science teaching and learning.

INCORPORATING INQUIRY IN SCIENCE INSTRUCTION

Although the conceptual frameworks and standards driving science education reforms have changed in the last two decades, “the practices of inquiry” (National Research Council, 2012, p. 218) have remained consistent as the focal point for instructional reform. An inquiry orientation to science instruction is grounded in the notion that “science is not just a body of knowledge that reflects current understanding of the world; it is also a set of practices used to establish, extend, and refine that knowledge. Both elements—knowledge and practice—are essential” (National Research Council, 2012, p. 26). Such an orientation is also grounded in the idea that students learn science best by engaging in the practices of science (Krajcik et al., 2008). Rather than simply learning scientific facts and skills, students in inquiry-oriented classrooms actively construct scientific knowledge through experience with how scientists build, evaluate, and apply scientific knowledge (Fensham & Harlen, 1999; Krajcik et al., 2008; Oliveira et al., 2013).

Calls to expand inquiry-oriented science instruction are grounded in research suggesting that this approach to teaching and learning science promotes higher order learning and engagement with science, a deeper understanding of science and engineering concepts, and 21st-century skills for scientific investigation and problem-solving (Bredderman, 1983; Furtak et al., 2012; Schroeder et al., 2007; Shymansky et al., 1990). Teachers’ use of inquiry-oriented curriculum materials and instructional frameworks such as the BSCS 5E instructional model (C. D. Wilson et al., 2009) and project-based science (Kanter & Konstantopoulos, 2010; Schneider et al., 2002) are also correlated with increased student achievement and attitudes toward science (Geier et al., 2008; Kahle et al., 2000; Marx et al., 2004).

Frameworks and standards that currently guide K–12 science education emphasize the role of inquiry in science instruction. The National Research Council’s National Science Education Standards articulated a vision for science education in which students develop scientific knowledge by experiencing authentic practices of science and engineering (National Research Council, 1996). The National Science Education Standards had broad implications for science teaching, characterizing inquiry teaching in terms of both how teachers go about engaging students and the types of learning activities in which teachers participate (Anderson, 2002). The dual focus on the characteristics of teaching and activities in which students participate is reflected the National Research Council’s A Framework for K-12 Science Education, which lists eight essential practices for inquiry-based classrooms: (1) asking scientific questions and defining problems; (2) developing and using models; (3) planning and carrying out investigations; (4) analyzing and interpreting data; (5) using mathematics and computational thinking; (6) constructing scientific explanations and designing solutions; (7) engaging in arguments based on science; and (8) obtaining, evaluating, and communicating information (National Research Council, 2012). NGSS is the most recent effort to redefine and deepen the notion of inquiry in science instruction by emphasizing the importance of teaching these practices (National Research Council, 2015). To date, more than 30 states have, in whole or in part, adopted NGSS. The emphasis on inquiry in K–12 science education is also evident in recent revisions to the NAEP to assess students’ conceptual understanding and knowledge of scientific and engineering practices. As the flagship national assessment, NAEP sets the bar for what U.S. students should know and be able to do in science for Grades 4, 8, and 10 (National Assessment Governing Board, 2009).

Despite the press for instructional reform, evidence suggests that teachers struggle to engage in inquiry-oriented science instruction (Roehrig et al., 2007). Factors such as teacher preparation to teach scientific inquiry (Banilower et al., 2013; Kolbe & Jorgenson, 2018), insufficient professional development (Smith et al., 2007), and access to instructional resources necessary for project-based learning (Barron et al., 1998; Fogleman et al., 2011; Roth et al., 2007) all have been identified as impacting the extent to which teachers incorporated inquiry-based instructional practices in their teaching. Other research suggests that the advent of rigid content standards and standards-based testing pressures may also discourage teachers from engaging in inquiry-oriented science instruction (Faulkner & Cook, 2006; Tretter & Jones, 2003).

In this study, we expand what is known about the factors that may impact teachers’ use of inquiry-oriented instructional practices in their science teaching. In the following sections, we review evidence in the literature that describes what is known about the relationship between the amount of time available for science instruction and the extent to which middle-level teachers engage in inquiry-oriented science instruction, controlling for the potential interrelationships with teacher qualifications and professional development.

INSTRUCTIONAL TIME AND SCIENCE TEACHING

Instructional time is a critical and costly educational resource that impacts students’ opportunities to learn. Put simply, students need sufficient time in school schedules to learn content and master skills (Berliner, 1990; Carroll, 1989), and teachers require sufficient time to prepare for and engage in effective classroom instruction (Patall et al., 2010).

Nascent research evidence suggests that the likelihood that teachers engage in reform-oriented science teaching—typified by inquiry-based instruction—can be impacted by the time available for instruction. Inquiry-oriented instruction requires teachers to have sufficient time to prepare lessons and facilitate learning activities that help students build the conceptual and procedural knowledge to engage in scientific reasoning and practice (Barron et al., 1998; Geier et al., 2008). Additionally, the level of teacher preparation and types of learning activities in which students engage may require longer and more frequently scheduled classes that exceed the discrete 40–55-minute blocks of time included in most eighth-graders’ school schedules (The Center for the Future of Teaching & Learning, 2012; Horn, 1992; Rice et al., 2002). While we know of no study that explicitly examines the impact of different amounts and arrays of instructional time in school schedules on teachers’ capacity and inclination to incorporate inquiry-oriented instructional practices in their science teaching, other research points toward the importance of instructional time for science teaching.

For instance, with more instructional time, teachers are likely to cover content in more depth and incorporate a wider variety of instructional strategies (Cooper et al., 2002; Rice et al., 2002); reinforce concepts and check understanding (Traphagen et al., 2011); incorporate more science experiments and other knowledge integration exercises (Clark & Linn, 2003; Horn, 1992); and provide opportunities for student discussion and debate (Traphagen et al., 2011). Furthermore, for optimal student learning to occur, studies have found that class time for science should be allocated regularly during the school day and week, without large gaps between teacher-student contact and opportunities for students to engage in learning activities; “science programs heavily weighted toward short teaching segments offered on an ad hoc schedule seem destined to fail” (Jones & Swanson, 2009, p. 188).

Conversely, when pressed for time, teachers are likely to scale back student investigations or omit hands-on activities altogether—either because they do not see a way to accomplish the task with less time or because, with insufficient time, the activity holds little value for student learning (Fogleman et al., 2011). When time is scarce, teachers also tend to revert to teacher-centered direct instructional practice (Blumenfeld et al., 1991; Romance & Vitale, 2006; Stage et al., 2013) and whole-group instruction (Banilower et al., 2010; Horn, 1992), and they may prioritize test preparation in lieu of developing skills that involve critical thinking and problem-solving (Faulkner & Cook, 2006; Traphagen et al., 2011). Together, these studies suggest that when faced with limited time, teachers will choose direct instructional approaches over inquiry-oriented instruction.

TEACHER QUALIFICATIONS AND INQUIRY-ORIENTED SCIENCE INSTRUCTION

It may also be the case that the effects of inquiry-based curricular materials and instructional frameworks are mediated by and dependent on a number of additional factors, including teachers’ science content knowledge (Kanter & Konstantopoulos, 2010), educational backgrounds (Kolbe & Jorgenson, 2018), and participation in professional development programs (Kahle et al., 2000; Krajcik et al., 1994). Teachers need both the content knowledge and instructional skill to engage in inquiry-oriented science instruction (Blumenfeld et al., 1991)—particularly the concepts, theories, laws, principles, history, and explanatory frameworks that organize and connect major ideas in science, as well as frameworks for thinking about laboratory work—that extends beyond a set of prescribed exercises for students in a place and time separate from the rest of science teaching (Windschitl, 2004).

Several studies investigated the relationship between science teachers’ educational backgrounds and their use of inquiry-based instructional practices. In their national study of nearly 3,500 K–6 teachers, Supovitz and Turner (2000) found that teachers’ perceptions of their content preparation in science was the strongest predictor for the extent to which they incorporated inquiry-based teaching practices and established an investigative culture in their classrooms. Smith and colleagues (2007) used data from previous iterations of the NAEP to examine relationships between eighth-grade teachers’ qualifications and their use of inquiry-based teaching in science and mathematics. They found that eighth-grade science teachers’ use of reform-oriented teaching practices was linked to their educational backgrounds, particularly whether teachers had academic majors in science disciplines. Kolbe and Jorgenson (2018), using data from the 2011 NAEP Eighth Grade Science Assessment, found that middle-level teachers’ educational backgrounds in science are related to the extent to which they use inquiry-based instructional practices, with more coursework and higher level degrees in science content areas associated with greater use.

A possible counterpoint to the importance of teachers’ educational backgrounds has been that teachers can acquire necessary knowledge and skills on the job—either through experience in the classroom or other professional development opportunities that occur during teachers’ tenure in the profession. For example, Kolbe and Jorgenson (2018) found that eighth-grade science teachers with at least 10 years of experience were more likely than novice teachers (with less than five years of experience) to use inquiry-oriented instructional practices in their science teaching. Similarly, in a mixed-methods study of 26 teachers in Grades 5–9, Capps and Crawford (2013) found that teachers who taught science as inquiry had a minimum of 10 years of experience teaching science.

Prior research also points toward participation in sustained professional development opportunities as boosting science teachers’ knowledge and skills in using inquiry-oriented teaching practices. For example, Supovitz and Turner (2000) found that science teachers who participated in inquiry-based professional development were more likely to establish an inquiry-oriented classrooms than those who did not receive similar training. Similarly, Banilower et al. (2007) found that teachers who participated in content-based professional development that was situated in classroom practice and sustained over time were more likely to foster an investigative culture and use investigative practices in their science teaching. Smith et al. (2007), using data from the 2000 Grade 8 NAEP science teacher survey, found a positive relationship between eighth-grade science teachers’ use of inquiry-oriented instructional approaches—incorporation of reporting and writing activities, emphasis on science concepts in teaching, and use of hands-on activities—and sustained participation in content-oriented professional development activities.

STUDY OVERVIEW

This study investigates the relationship between the amount of time allocated for science instruction in a given week and the extent to which eighth-grade science teachers used inquiry-oriented instruction in their teaching. We also consider whether the relationship between time and instructional practice is affected by teachers’ content knowledge in science and participation in professional development related to inquiry-based science instruction. Teacher content knowledge and professional development participation, in particular, have been shown to influence middle-level science teachers’ instructional practice (Kolbe & Jorgenson, 2018; Smith et al., 2007; Supovitz & Turner, 2000). Specifically, we consider two research questions: (1) To what extent is teachers’ use of inquiry-oriented instructional practices related to the time available for science instruction during the school week? (2) To what extent do differences in teachers’ professional training to teach science impact the relationship between instructional time and science teachers’ use of inquiry-based instructional practices? To answer these questions, we used data from a large national sample of eighth-grade science teachers who participated in the NAEP’s 2011 Grade 8 science assessment. The teacher survey includes a measure of the number of hours in the school week allocated for science instruction, a range of indicators describing teachers’ instructional practice, and information about teachers’ educational backgrounds and professional training.

DATA AND METHODS

DATA

The NAEP’s 2011 Grade 8 science assessment included a survey of teachers whose students participated in the assessment. The teacher survey captures information on the amount of time teachers spent on science instruction; their qualifications, education, and professional development related to science instruction; and measures intended to gauge the extent to which teachers use inquiry-oriented instruction (National Assessment Governing Board, 2009). While other large national surveys include samples of teachers (e.g., the Schools and Staffing Survey), the NAEP is the only large, national survey that captures information on how teachers teach science, time spent on science instruction, and teacher knowledge and skills.

NAEP restricted use data for the Grade 8 science assessment are organized as student- and school-level data files, with teacher questionnaire responses appended to student-level observations. To create a teacher-level data file, we collapsed responses so that one observation per teacher remained. To reflect the population of public schools and teachers, we limited our analytic sample to teachers in noncharter public schools.¹ We then appended school information to each teacher-level observation using the NAEP’s school-level data files. The resulting analytic sample included approximately 11,520 teachers in 6,850 public schools.

MEASURES

Measures used in our analysis fell into four broad categories: (1) teachers’ use of inquiry-based instructional practices; (2) time spent on science instruction; (3) teacher education and training; (4) teacher professional development; and (5) other teacher- and school-level controls (Table 1).

Table 1. Key Variables and Descriptive Statistics

^a About how much time in total do you spend with this class on science instruction in a typical week?

^b From the NAEP teacher questionnaire: Did you have a major, minor, or special emphasis in any of the following subjects as part of your [graduate/undergraduate] coursework? (a) Biology or other life science (b) Earth or space science (c) Engineering or engineering education (d) Physics, chemistry, or other physical science

^c From the NAEP teacher questionnaire: Did you have a major, minor, or special emphasis in any of the following subjects as part of your [graduate/undergraduate] coursework? (e) Science education (major, minor or special emphasis, No) (1 = major or minor in science education at graduate or undergraduate level; 0 = no major or minor in science education at any level)

^d Consider all the professional development activities you participated in during the last two years. To what extent did you learn about scientific inquiry and/or technological design?  (1 = not at all, 2 = small extent, 3 = moderate extent, 4 = large extent)

^e Did you enter teaching through an alternative certification program? (1 = Yes, 0 = No)

^f How many students are in this class for science?  

^g Students assigned to class by ability (1 = Yes, 0 = No)

^h How many years have you taught science in Grades 6–12?

ⁱ What is the current enrollment in your school? (school-reported as an open-ended answer, then categorized into one of five ranges)

^j During this school year, about what percentage of students in your school were eligible to receive a free or reduced-price lunch through the National School Lunch Program?  (0%, 1%–5%, 6%–10%, 11%–25%, 26%–34%, 35%–50%, 51%–75%, 76%–99%, 100%)

^k Approximately what percentage of students in your school receive the following services? Report the percentage who receive each of the following services as of the day you respond to this questionnaire: Special education (None, 1%–5%, 6%–10%, 11%–25%, 26%–50%, 51%–75%, 76%–90%, Over 90%)

^l To what extent is your school’s science program structured according to state curriculum standards or frameworks?

^m To what extent is your school’s science program structured according to results from state/district assessments?

ⁿ To what extent does your school’s eighth-grade science curriculum focus on preparation for state assessments?

^o Type of community where school is located, based on Census data describing proximity to an urbanized area (a densely settled core with densely settled surrounding areas) using four categories

Inquiry-Oriented Science Instruction

Acknowledging the multidimensionality of inquiry-oriented science instruction, we developed a composite measure to describe teachers’ instructional practice. To do so, we built on an earlier composite measure developed by Smith et al. (2007) using the NAEP’s 2000 Grade 8 science assessment teacher survey. This measure was updated by Kolbe and Jorgenson (2018) in their study of the relationship between teachers’ educational backgrounds and inquiry-oriented instructional practices. We used this updated measure in our analysis. In the following sections, we describe how the updated measure was created and specifically built on the earlier work by Smith and colleagues (2007).

Smith et al. (2007) developed a measure of inquiry-oriented instruction based on teachers’ use of four inquiry-oriented teaching strategies: (1) procedural activities, (2) reporting and writing activities, (3) hands-on activities, and (4) and emphasis on conceptual objectives. Our composite measure incorporated 18 items, including both carryover items from Smith and colleagues’ (2007) measure and teacher response data from several new survey questions that asked teachers about how and to what extent they integrated scientific problem-solving in their teaching (Appendix A). Given the response variables’ ordinal structure, we used principal components analysis with polychoric correlations to group items into subscales corresponding to different dimensions of inquiry-oriented instruction. Varimax rotation was used to differentiate variables by extracted factors so that each variable was identified with a single factor.

Selected items loaded onto four components, each with eigenvalues greater than 1. Altogether, the resulting components explained 65.3% of the variance across items (Appendix A). Three of the four components were consistent with Smith and colleagues’ (2007) work: (1) emphasis on conceptual objectives (α =.83); (2) use of hands-on activities (α =.79); and (3) reporting and writing activities (α =.62). We could not replicate Smith and colleagues’ fourth factor: teachers’ use of procedural activities. Instead, we identified a new fourth dimension: scientific problem-solving (α =.76). This new factor included items added to the 2011 NAEP Grade 8 science assessment’s teacher survey that describe the extent to which teachers asked students to engage in scientific problem-solving, identify questions for investigation, and discuss problems that scientists and engineers are asked to solve. We combined the four components into a single scale based on the unweighted average of the four separate factors (α = .89).² The composite measure was standardized to have a mean of 0 and a standard deviation of 1. A key strength of the resulting composite measure is that it includes multiple teaching strategies that are conceptually aligned with how inquiry-oriented instruction is defined and understood within the science education community.³

Time Spent on Science Instruction

Teachers answered one question about how much time in a typical week they spent on science instruction for the class to which students participating in the NAEP science assessment were assigned. Teachers responded according to the following categories: less than 1 hour; 1–2.9 hours; 3–4.9 hours, 5–6.9 hours, and 7 hours or more. Nearly two thirds of eighth-grade teachers (61%) reported spending between 3 and 4.9 hours per week on science instruction (Table 1). About one quarter of teachers (26%) spent between 5 and 6.9 hours per week, and 7% spent 7 or more hours per week teaching science. The questionnaire did not include other questions about how time was allocated during a typical week (e.g., an hour each day) or the number of days per week they taught science. We created dichotomous variables (yes/no) for each response category, combining the lowest two categories into one indicating less than 3 hours of instructional time. About 6% of participating teachers reported that they had less than 3 hours per week for science instruction. In our models, we use 3–4.9 hours per week of instructional time as our reference category (i.e., the amount of instructional time that was most commonly reported by eighth-grade science teachers).

Teacher Education and Training

Our analysis included several measures that describe different aspects of teachers’ education and training related to science teaching. Middle-level teachers’ educational backgrounds, particularly whether they have an undergraduate or graduate degree in engineering or a science discipline, or specialized postsecondary education or degrees in science education, are associated with incorporating scientific inquiry and inquiry-oriented instructional practices in teaching (Kolbe & Jorgenson, 2018; Smith et al., 2007).   

Teachers reported whether they had a degree in a science-related discipline, including biology or other life science, earth or space science, physics, chemistry, or other physical science, and engineering. We created indicator variables that classified teachers according to the highest degree held in a science-related discipline: (1) graduate degree, (2) undergraduate major, (3) undergraduate minor, and 4) no degree. We also constructed an indicator for a teacher who held an education-related degree or other credential specific to science education.

We did not include an indicator for whether teachers were certified to teach in their state, given that teacher certification was nearly universal in the NAEP sample. In its place, we opted to include an indicator for whether a teacher was alternatively certified. Teachers who obtain licensure through alternative routes typically have less formal training in teaching and instructional practice, but they may be more likely to have professional work experience and applied skills in science, technology, mathematics, or engineering outside of education (Good et al., 2006; Ketelhut & Newton, 2011). This professional experience might better equip alternatively certified teachers to improve student learning in how to “do” science, a core tenet of inquiry-based science instruction. Alternatively, less formal training in how to teach science might hamper alternatively certified teachers’ efforts to use inquiry-oriented practices in their classrooms.

Our models also controlled for teachers’ experience teaching science. Specifically, the NAEP teacher questionnaire asks teachers to classify their experience teaching science according to four categories: (1) < 5 years, (2) 5–9 years, (3) 10–19 years, and (4) 20 years or more. We developed an indicator variable (yes/no) for each experience category; we used teachers with 5–9 years of experience as the reference category in our analysis.

Teacher Professional Development

Professional development that is focused on boosting teachers’ knowledge and skills in inquiry-oriented instruction may also increase the likelihood that science teachers incorporate inquiry-oriented instructional practices in their teaching (Kolbe & Jorgenson, 2018; Smith et al., 2007; Supovitz & Turner, 2000). Teachers were asked to report the extent to which they participated in professional development focused on “scientific inquiry” in the past two years. In our analysis, we compared teachers who responded “not at all,” “to a small extent,” “to a moderate extent,” and “to a large extent” according to the extent they engaged in professional development related to inquiry-oriented science instruction. In our models, we compared teachers with different levels of professional development experience with those who replied “not at all” (i.e., reference category).

Classroom Context

We also controlled for two teacher-reported characteristics of the classroom context: (1) class size and (2) whether students were assigned to a class based on “ability.” We recoded the class size variable using the midpoint for each category: (1) < 15 students, (2) 16–20 students, (3) 21–25 students, and (4) 26 or more students. The “ability” grouping variable was a binary response (yes/no) for teachers.

School Characteristics

For schools, we incorporated measures that accounted for differences in student demographics and organizational context among schools. We included a measure for school size, as measured by student enrollment. We recoded the student enrollment variable using the midpoint for each category: (1) 1–399 students, (2) 400–599 students, (3) 600–799 students, (4) 800–999 students, and (5) 1,000 or more students. As a proxy for the extent to which a school served economically disadvantaged students, we also included a measure for the percentage of students eligible for free or reduced-price lunch. The NAEP reports this information as a categorical variable: (1) None, (2) 1%–5%, (3) 6%–10%, (4) 11%–25%, (5) 26%–50%, (6) 51%–75%, (7) 76%–90%, and (8) Over 90%. We recoded this variable as the midpoint for each category. We used the percentage of students receiving special education and related services in a school to control for share of students with different learning needs; this categorical variable was similarly recoded based on the midpoint for each category. Finally, we included indicators for a school’s location—that is, whether a school resided in a city, suburb, town, or rural area.

In addition, the models included three indicators that captured aspects of schools’ decisions related to science curriculum and instruction: the extent to which a school’s science program was (1) structured around state standards, (2) structured around state or district assessment results, and (3) focused on preparing students for state assessments.

ANALYTIC APPROACH

We used a two-level multilevel linear model to predict teachers’ scores on our composite measures describing inquiry-based instructional practices as a function of instructional time and teachers’ education and professional training in science instruction (Level 1), controlling for a range of teacher (Level 1) and school (Level 2) characteristics. We then introduced teacher-level interactions between our measures of instructional time and whether a teacher (1) had an undergraduate or graduate major in a science field, (2) was a science education major, and (3) participated in professional development focused on scientific inquiry “to a large extent.”

To make our findings more closely represent the sample of assessed students, we adjusted our sample using the NAEP’s school-level sampling weights. Weighting the data in this manner corrects for the oversampling of schools that occurs in the context of the NAEP’s complex sample design. Although imperfect, this weighting strategy provides teacher-level estimates that approximate a nationally representative sample of eighth-grade public school science teachers (Kolbe & Jorgenson, 2018; Smith et al., 2007).

We estimated five models. The first model looked at the relationship between the extent to which teachers used inquiry-oriented instructional practices and the amount of time available for instruction (Model 1). Model 2 incorporated indicators for what teachers know and can do in the classroom, as well as controls for teacher qualifications and school characteristics. Models 3–5 included interaction terms between indicator variables for different amounts of instructional time and teachers’ degrees in science (Model 3) and science education (Model 5), and professional development participation in the past two years (Model 4).

We evaluated our models for potential violations in assumptions for the statistical tests that were used. All assumptions for linearity between the independent and dependent variables were met. Correlations among all teacher-level and school-level variables included in our models were also considered. Among both teacher- and school-level variables, correlations were sufficiently small to suggest that multicollinearity is not a cause for concern when interpreting the coefficients for key independent variables of interest. (Correlations among independent variables included in our models are provided as Tables B1 and B2 in Appendix B.) Finally, in evaluating our models, we did not find evidence of heteroskedasticity.

FINDINGS

We present findings according to the study’s two research questions. First, we examine the extent to which teachers’ use of inquiry-oriented instructional practices was related to the time available for science instruction. We then look at whether the nature of this relationship was related to teachers’ educational backgrounds and professional development.

TIME AVAILABLE FOR SCIENCE INSTRUCTION

The extent to which eighth-grade science teachers incorporated inquiry-oriented instructional practices in their teaching was related to the amount of time available for science instruction in a school week. In particular, teachers with five or more instructional hours per week were more likely than their counterparts with less time to use inquiry-oriented instructional practices in their science classes. Having 5–6.9 hours per week for science instruction was associated with a 27% of a standard deviation increase in the use of inquiry-oriented instructional practices, compared with the national norm of 3–4.9 hours per week (Table 2, Model 1). Similarly, 7 or more hours per week of instructional time was associated with 46% of a standard deviation increase in the extent to which inquiry-oriented instructional practices were used. The difference between teachers with 3–4.9 hours of instructional time and those with 3 hours or less was small—about 15% of a standard deviation.

Table 2. Predicting Teachers’ Use of Inquiry-oriented Instructional Practices: Overall Scale

Note.  For Model 1, sample size = 10,170 students; 5,100 groups. For Models 2, 4, and 5, sample size = 8,020 students; 4,290 groups. For Model 3, sample size = 8,250 students; 4,350 groups. Unstandardized coefficients are shown with robust standard errors in parentheses. School enrollments based on categorical medians, class size, percentage free and reduced-price lunch, and percentage special education are grand mean centered.

^†p < .10 *p < .05 **p < .01 ***p < .001.

When we looked at the four factors that comprised our overall measure, we found that the relationship between time and teachers’ emphasis on science concepts was comparable with those found for the overall measure; teachers with more time were more likely to emphasize science concepts in their teaching (Table 3, Model 1). However, for the other factors, there was no difference in the relationship between time and instructional practices for teachers with less than 3 hours and those with 3–4.9 hours per week (Tables 4–6, Model 1). This suggests that teachers increased their use of hands-on activities, scientific problem-solving, and reporting and writing activities when they had 5 or more hours of instructional time per week. However, there was no difference in the extent to which these practices were used among teachers with less than 3 hours and those with 3–4.9 hours per week for science instruction.

Table 3. Predicting Teachers’ Use of Inquiry-Oriented Instructional Practices: Conceptual Emphasis (Factor 1)

Note.  For Model 1, sample size = 10,170 students; 5,100 groups. For Models 2, 4, and 5, sample size = 8,020 students; 4,290 groups. For Model 3, sample size = 8,250 students; 4,350 groups. Unstandardized coefficients are shown with robust standard errors in parentheses. School enrollments based on categorical medians, class size, percentage free and reduced-price lunch, and percentage special education are grand mean centered.

^†p < .10. *p < .05. **p < .01. ***p < .001.

When we controlled for teacher qualifications in our models, there was no longer a statistically significant difference in practices between teachers who reported 3–4.9 hours per week and those with 3 hours or less (Table 2, Model 2). Controlling for teacher qualifications also decreased the magnitude of the coefficients on the time indicators for teachers with 5 or more hours of time per week. Despite the decrease in magnitude, there was still a moderate to strong relationship between instructional time and teachers’ use of inquiry-oriented instructional practices; having 5–6.9 hours per week was associated with 21% of a standard deviation increase (compared with 3–4.9 hours) in inquiry-oriented instructional practices, and a 34% increase when teachers had 7 or more hours per week.

Table 4. Predicting Teachers’ Use of Inquiry-Oriented Instructional Practices: Use of Hands-On Activities (Factor 2)

Note.  For Model 1, sample size = 10,170 students; 5,100 groups. For Models 2, 4, and 5, sample size = 8,020 students; 4,290 groups. For Model 3, sample size = 8,250 students; 4,350 groups. Unstandardized coefficients are shown with robust standard errors in parentheses. School enrollments based on categorical medians, class size, percentage free and reduced-price lunch, and percentage special education are grand mean centered.

^†p < .10. *p < .05. **p < .01. ***p < .001.

There were analogous patterns in the relationship between instructional time and each of the four factors that comprised our overall measure of inquiry-oriented instructional practices (Tables 3–6, Model 2). The one exception was the model predicting teachers’ conceptual emphasis in their teaching (Table 3, Model 2). Here, we found that teachers with less than 3 hours of instructional time per week emphasized science concepts to a lesser extent than their peers reporting 3–4.9 hours per week (.17 standard deviation difference).

We also found independent relationships, albeit smaller in magnitude, between teachers’ educational backgrounds and their use of inquiry-oriented instructional practices in their science teaching (Table 2, Model 2). Having a graduate major in science was associated with a 15% of a standard deviation increase in the use of inquiry-oriented instructional practices, compared with teachers without an academic major in science and engineering. The difference between teachers with undergraduate majors and those without an academic major was 6% of a standard deviation. Whether a teacher had a science education major or minor also increased the likelihood that a teacher would use inquiry-oriented instructional practices—about 12% of a standard deviation—compared with teachers without a science education degree.

Alternatively certified teachers were more likely (9% of a standard deviation) to incorporate inquiry-oriented instructional practices in their science teaching, compared with conventionally certified teachers (Table 2, Model 2). However, this relationship looked different across the four factors comprising our overall measure. Alternatively certified teachers emphasized science concepts (8% of a standard deviation; Table 3, Model 2) and emphasized doing inquiry in science (16% of a standard deviation; Table 5, Model 2) in their teaching to greater extents than other teachers. There was no difference between alternatively certified and other teachers in the extent to which hands-on instruction and reporting and writing activities were used.

Table 5. Predicting Teachers’ Use of Inquiry-Oriented Instructional Practices: Emphasis on Doing Inquiry (Factor 3)

Note. For Model 1, sample size = 10,170 students; 5,100 groups. For Models 2, 4, and 5, sample size = 8,020 students; 4,290 groups. For Model 3, sample size = 8,250 students; 4,350 groups. Unstandardized coefficients are shown with robust standard errors in parentheses. School enrollments based on categorical medians, class size, percentage free and reduced-price lunch, and percentage special education are grand mean centered.

^†p < .10. *p < .05. **p < .01. ***p < .001.

Teachers’ participation in professional development activities focused on inquiry in instruction was strongly related to the extent to which they used inquiry-oriented instructional practices (Table 2, Model 2). Participating to a “large extent” in the past two years was associated with a 113% increase in the extent to which teachers engaged in inquiry-oriented instruction. Moreover, even modest participation seemed to support teachers using these practices to a greater extent. Participating to a “small extent” was associated with a 39% of a standard deviation increase in inquiry-oriented instruction, and a “moderate extent” associated with a 74% increase.

Our findings suggest that the contributions of school context—after accounting for teachers’ education, professional training, and experience—have almost no relationship with eighth-grade science teachers’ use of inquiry-oriented instructional practices. Across multiple measures of teachers’ instructional practice, we found weak or no relationships between school size, the share of students attending a school who are eligible for free or reduced-price lunch, or the percentage of students receiving special education and the extent to which teachers engage in inquiry-oriented science instruction. Teachers in urban schools were somewhat less likely than their peers working in suburban schools (about 10% of a standard deviation difference) to emphasize science concepts in their teaching (Table, 3, Models 1 and 2).

Instead, our findings suggest that state and district policies directed at schools’ science programs are associated with teachers’ instructional practice. Specifically, teachers in schools focused on preparing students for state science assessments were less likely to use inquiry-oriented instructional practices in their teaching. Teaching in an assessment-focused school was associated with 6% of a standard deviation decline in teachers’ use of inquiry-oriented instructional practices (Table 2, Model 2). That said, an assessment focus appeared to impact certain dimensions of inquiry-oriented instruction more than others. Teachers in schools with science programs structured to a large extent around state standards were less likely to engage in practices that emphasized “doing inquiry” in science (9% of a standard deviation; Table 5, Model 2). Teachers in schools that focused on preparing students for state assessments also were less likely to incorporate reporting and writing activities in their science teaching (15% of a standard deviation; Table 6, Model 2).  Teaching in an assessment-focused school was unrelated to whether teachers emphasized science concepts or engaged in hands-on instruction.

Table 6. Predicting Teachers’ Use of Inquiry-Oriented Instructional Practices: Reporting and Writing Activities (Factor 4)

Note. For Model 1, sample size = 10,170 students; 5,100 groups. For Models 2, 4, and 5, sample size = 8,020 students; 4,290 groups. For Model 3, sample size = 8,250 students; 4,350 groups. Unstandardized coefficients are shown with robust standard errors in parentheses. School enrollments based on categorical medians, class size, percentage free and reduced-price lunch, and percentage special education are grand mean centered.

^†p < .10. *p < .05. **p < .01. ***p < .001.

TEACHERS’ EDUCATIONAL BACKGROUNDS AND PROFESSIONAL DEVELOPMENT

We incorporated interactions in our models to capture the joint effects of instructional time with teachers’ content knowledge in science, preparation to teach science, and participation in professional development related to inquiry-based science instruction on the extent to which teachers used inquiry-based instructional practices. For these interaction terms, a positive coefficient for an interaction term suggests that instructional time is likely to have a stronger relationship with teachers’ use of inquiry-based instructional practices if they have a graduate or undergraduate degree in a science content area or science education or have participated in professional development on inquiry-based science instruction. That is, instructional time and teacher education and other professional training to teach science may work together to increase the extent to which inquiry-oriented instruction is used in the classroom. Conversely, a negative coefficient could suggest that instructional time had a stronger relationship with instructional practice for teachers without degrees in a science content area or science education, or professional development.

In Model 3, we looked at interactions between different amounts of instructional time and whether teachers had a graduate or undergraduate degree in a science content area. We did not find significant interactions between time and teachers’ degrees in science for our overall measure of teachers’ use of inquiry-oriented instruction (Table 2, Model 3). However, we did find statistically significant interactions for two of the factors that made up our overall scale: (1) conceptual emphasis in teaching (Table 3, Model 3) and (2) emphasis on doing inquiry in science (Table 5, Model 3).

First, for the extent to which teachers emphasized scientific concepts in their teaching, we found negative interaction coefficients between 5 and 6.9 hours and whether teachers had an academic major in a science content area (Table 3, Model 3; B = -0.14, p = .042). This implies that with more instructional time, teachers with potentially less content knowledge were more likely to emphasize science concepts in their teaching. Second, for the extent to which teachers emphasized doing scientific inquiry in their teaching, we found a positive interaction between having 7 or more hours per week of instructional time and teachers’ content knowledge (Table 5, Model 3; B = 0.21, p = .046). This suggests that teachers with more time to teach science and potentially more content knowledge emphasized the process of scientific inquiry to a greater extent in their teaching.

In Model 4, we considered interactions between instructional time and teachers’ participation in professional development related to inquiry. Specifically, we interacted our time variables with whether teachers participated in inquiry-related professional development “to a great extent.” For our overall measure of teachers’ use of inquiry-oriented instruction, we found a statistically significant positive interaction term between teachers’ having participated in professional development related to inquiry “to a great extent” and having 7 or more hours of instructional time for science per week (Table 2, Model 4; B = 0.18, p = .062). This suggests that teachers who participated in inquiry-related professional development may have been better able to use larger amounts of instructional time (i.e., 7 or more hours per week) to incorporate inquiry-oriented instructional practices in their teaching than those who had participated in professional development to a lesser extent.

In Model 5, we interacted our instructional time measures with an indicator for whether teachers held a science education degree (undergraduate or graduate). We found statistically significant negative interaction terms between teachers with science education degrees (major or minor) and whether teachers had 0–2.9, 5–6.9, or 7 or more hours of instructional time per week (Table 2, Model 5). These findings suggest that teachers without a science education degree may be better able to incorporate inquiry-oriented instructional practices in their science teaching with more instructional time. We illustrate these patterns in Figure 1, where the predicted values are depicted for the extent to which teachers use inquiry-oriented instructional practices (the y-axis) in their teaching according to the time available for teaching (the x-axis), for teachers with and without a science education degree at the undergraduate or graduate levels. Here, we can see that although teachers with science education degrees are generally more likely to incorporate inquiry-oriented teaching practices in their instruction, there is a convergence in predicted values of instruction for teachers with and without science education degrees as teachers have more time to teach. This finding suggests that with additional instructional time, teachers without science education degrees may be able to close the gap in instructional practice with teachers who hold such degrees.

Figure 1. Predicted values for teachers’ use of inquiry-oriented instruction, by teacher degree in science education (Table 2, Model 5)

LIMITATIONS

The study’s findings are not without limitations. First, our analysis was constrained because the NAEP survey asks teachers to report instructional time according to preset categories rather than a continuous measure of the hours or minutes per week of time available. The categories are coarse measures, with set cut points that may not be instructionally meaningful. Additionally, given the ranges represented by the categories (e.g., 3–4.9 hours; < 3 hours), we cannot evaluate the potential effects of small differences in time (e.g., 4.75 vs. 5.25 hours per week). Our findings for instructional time should be considered with these limitations in mind. That said, that we found consistent relationships between instructional time and teacher practice suggests that time is a relevant consideration as efforts move forward to expand the use of inquiry-oriented instruction in middle-level classrooms.  

Second, our measure of teachers’ instructional practice is based on teacher self-reports of instructional strategies. We are sensitive to concerns that teacher survey responses may be less convincing than actual observations of teacher practice or links to student outcomes, and that it could be socially desirable for science teachers to report that they use reform-oriented teaching strategies (Hamilton et al., 2016). Research on surveys of teaching practice suggests that surveys can be effective in describing and discriminating among teachers’ instructional practice (Mayer, 1999; Mullens & Gayler, 1999; Mullens & Kasprzyk, 1999; Ross et al., 2003), particularly when composite measures with multiple indicators are used (Mayer, 1999). And, although overreporting desirable behaviors and practices is an established risk factor in survey research, the likelihood for bias may be less when data collection is confidential and nonevaluative (Mayer, 1999). It also is the case that the NAEP science assessment teacher survey was developed by survey experts, education researchers, teachers, and statisticians to ensure data quality, and questions were tested with teachers before final selection. Taken together, these considerations provide us with a reasonable degree of confidence in the indicators used in this study.

Third, our analysis was constrained to items included on the NAEP assessment. As a result, other indicators and controls of interest not included on the NAEP are unaccounted for in our models. For example, information about teachers’ in-service experiences could provide additional insights into other aspects of professional learning that affect how teachers teach science. The NAEP survey’s cross-sectional sample design also prevents us from examining potential impacts of instructional time and teachers’ practice on student outcomes.

This study also purposefully focuses on one aspect of reform-oriented science teaching (inquiry-oriented instruction) and resources (instructional time and teacher qualifications) that might influence its use. This is not to say that these are the only conditions that might impact the extent to which middle-level science teachers incorporate inquiry-oriented instructional practices in their teaching. Other potential influencers, especially teachers’ beliefs about how science should be taught, may also play an important role in the extent to which inquiry-oriented practices are used (Blumenfeld et al., 1991). However, the NAEP data do not include variables that would support additional analyses that control for teachers’ attitudes and beliefs about how science should be taught.

Finally, observational data, such as those collected by the NAEP, are insufficient evidence for establishing causal relationships between instructional time and teacher practice. For instance, schools with policies, programs, and resources in place to encourage inquiry-oriented science instruction may also prioritize time for science instruction in their school schedules. Rather, the study’s findings are correlational and describe observed relationships between time available for science instruction and instructional practice. We believe these relationships to be useful in stimulating discussion and further research.

DISCUSSION

As districts and schools face increased pressure to encourage and support science teachers’ use of inquiry-oriented instructional practices, it is important to understand how the amount of time available for science instruction impacts teachers’ abilities to incorporate these practices in their teaching. However, to date, the likelihood that teachers use inquiry-based instructional practices has only been loosely linked to school contextual factors and resources, as well as teacher qualifications.

Findings from this study further our understanding of these relationships in several important ways. First, the study’s findings suggest that teachers use inquiry-oriented instructional practices to a greater extent when they have more time to teach science, and they are increasingly able to do so with additional increments of instructional time. At the same time, we found evidence of a threshold effect at 5 hours per week for increasing the extent to which inquiry-oriented instructional practices are used; there was no difference in instructional practice between teachers with less than 3 hours and those with 3–4.9 hours per week. This finding is particularly striking given that the majority of teachers who participated in the NAEP survey reported having 3–4.9 hours per week. Taken together, these findings support claims that instructional time contributes to teachers’ capacity to incorporate inquiry-oriented instruction in their science teaching (Marx & Harris, 2006; Shields et al., 2011; Traphagen & Johnson-Staub, 2010). The Center for the Future of Teaching & Learning (2012) suggested a rationale for why this may be the case:

Preparing for, engaging students in, and breaking down and cleaning up after a hands-on learning activity pushes the bounds of standard 50 or 55-minute instructional period. Thus, while middle schools dedicate some time for science instruction, it may not be enough time or the time may not be scheduled in a way that accommodates experiential learning opportunities. (p. 4)

In fact, when we look at the relationship between instructional time and the dimensions of inquiry-oriented instructional practice considered in this study, we see patterns consistent with the Center’s observation. We found that teachers steadily increased the extent to which they emphasized science concepts in their teaching as they had more instructional time. When using curricular units intended to facilitate students’ conceptual understanding, teachers and students needed sufficient instructional time to integrate understanding (Clark & Linn, 2003). We also found that other aspects of inquiry-oriented instructional practice may have some threshold, or minimum amount of instructional time, to increase their use. Teachers with at least 5 hours of instructional time per week—the equivalent of at least 60 minutes per day during a five-day school week—used hands-on activities, scientific problem-solving, and reporting and writing activities to a greater extent. Moreover, there were no differences in the extent to which these practices were used between teachers with about 35 minutes per day, and teachers with 36–59 minutes per day (assuming a five-day-per-week class schedule).

Second, for the most part, the relationship between instructional time and teachers’ practice is independent of teacher qualifications. When controls for a broad range of conceptually relevant teacher qualifications were added to our models, the association between instructional time and teachers’ use of inquiry-oriented instruction remained was largely unchanged for time periods larger than 5 hours per week. And, although the magnitude of these associations decreased, their size remained moderate to large. This finding suggests that while investments in teacher education and professional training to teach science are important considerations, so too is the amount of time available for science instruction. With insufficient time, even the most qualified teachers may struggle to engage in reform-oriented science teaching.  

This is not to say that teacher qualifications are unrelated to the extent to which inquiry-based instructional practices are used. In fact, our study reaffirms existing research suggesting that teachers’ educational backgrounds in science, proxies for teachers’ content knowledge, play a role in the extent to which middle-grades teachers engage in reform-oriented science instruction. Similarly, teachers with degrees in science education were also more likely to engage in inquiry-based science teaching. Moreover, teachers who participated in professional development related to inquiry-based science teaching were more likely to incorporate these practices with additional training. Altogether, the relationships between middle-level science teacher qualifications and instructional practice are notable given the educational backgrounds of teachers included in our sample. Slightly less than half (48%) of the eighth-grade teachers included in our sample held an undergraduate or graduate degree in a science discipline, and just 56% reported having a science education degree.

Apart from the independent relationships between teachers’ qualifications and instructional practice, our findings also imply that teachers’ educational backgrounds to teach science may offset some of the effects of having less instructional time; that is, teachers with degrees in science education may be better equipped to use inquiry-based instructional practices in situations in which less time is available for instruction in a given week. Although teachers’ educational backgrounds do not entirely offset the relationship between instructional time and teacher practice, it is noteworthy that there may be a substitution effect between instructional time and teacher preparation for teaching science. This suggests that educational policy makers and leaders charged with decisions about how to invest scarce resources might weigh the costs and potential benefits of investing in teacher education and professional training to teach science versus additional increments of instructional time for science.

Finally, our findings suggest that, in and of themselves, school characteristics are not strongly associated with how teachers teach science. Instead, we found that other policy-malleable variables—notably instructional time and teacher education and professional development—were the most consistent and strongest predictors of the extent to which teachers engaged in inquiry-oriented science instruction. These findings point toward an opportunity for policy makers and educational leaders to increase the use of inquiry-oriented science instruction through targeted investments in instructional time and teacher talent, regardless of school context. The study’s findings also provide additional evidence regarding the relationship between science teachers’ qualifications and their instructional practice. In their study, Kolbe and Jorgenson (2018) found that teacher content knowledge and pedagogical training in science education shaped teachers’ capacity to teach science as inquiry. Taken together, this study and the earlier work by Kolbe and Jorgenson (2018) suggest that attending to differences in teacher knowledge and skills among schools is a necessary step toward ensuring that all students have an equal opportunity to experience in science as inquiry.   

IMPLICATIONS

The study suggests that schools will be challenged to reach the goals set forward by NGSS and other efforts to reform science education without serious consideration of the types of investments that may be required. Findings speak directly to policy makers and educators about the resources—especially investments in instructional time and teacher qualifications—that may be needed to expand middle-level science teachers’ use of inquiry-oriented instructional practices. Efforts to increase the extent to which science teachers incorporate inquiry-based instructional practices in their teaching may be confounded by the amount of time available to teach science. Nearly two thirds of eighth-grade students nationwide receive less than 5 hours of science instruction in a typical school week. Yet we see that only with levels of instructional time that exceed this threshold do teachers appear to increase their use of hands-on, problem-solving, and reporting and writing activities aligned with an inquiry orientation to learning about science.  

However, simply increasing instructional time may not go far enough to support the types of reform-oriented teaching envisioned by current standards and guidance. Many middle-level science teachers may lack the education and professional training they need to effectively engage in inquiry-based science instruction. Our findings reaffirm past research that points to teachers’ content knowledge in science disciplines and training in how to teach science also playing a role in the extent to which teachers engage in reform-oriented science instruction (Kolbe & Jorgenson, 2018; Smith et al., 2007). This raises questions, however, about existing policies and programs that minimize content knowledge requirements for middle-level teachers and that allow teachers without subject-specific pedagogical training to be assigned to teach science. For instance, state policies that allow elementary-level certification or licensure to overlap with the upper middle grades represent one source of concern, as do state policies and practices that do not require postsecondary degrees or substantial advanced coursework in science as qualifications for middle-level science teachers. Subject matter tests that limit their assessment to topics covered by the curriculum also may be problematic by providing weak signals for whether teachers have the breadth and depth of knowledge needed to facilitate student learning and investigation (Wilson, 2016).

Looking forward, there is a continued need to explore the relationships between instructional time, teacher practice, and science achievement. Outside pressure to respond to calls for improved student achievement in science is palatable. On the one hand, the study’s findings reinforce that time is a critical school resource—impacting both students’ opportunities to learn and teachers’ capacity to engage in reform-oriented science instruction. Yet, practically, policy makers and educational leaders need more and better information about how instructional time for science may enable or constrain the types of reform-oriented science teaching that is typified by inquiry-oriented instructional practices.

Notes

1.

Our analytic sample of teachers and schools was limited to noncharter public schools. To arrive at this sample, we dropped observations from the sample of schools participating in the NAEP’s Grade 8 science assessment that were identified as “private,” “other,” “public charter,” “special education,” “alternative,” “private religious,” and “other type of school.” The NAEP survey did not, however, collect information on whether the remaining public schools were magnet or other type of school that might offer a specialized science (or nonscience) curriculum. Accordingly, it is possible that some schools in the sample offer this type of programming, and this could account for differences in the amount of time teachers reported spending on science instruction.

2.

Smith et al. (2007) reported findings for each subscale separately. For parsimony, we chose to combine the subscales into a single proxy measure that describes the extent to which teachers engaged in inquiry-oriented science instruction.

3.

The inquiry-oriented composite measure and its subscales allow for relative comparisons among teachers with respect to the extent to which inquiry-oriented instructional practices were used; however, the scale does not speak to whether inquiry-oriented science instruction is used to the extent desired or intended. Presently, specific benchmarks or thresholds for measuring teacher instructional practice do not exist. Rather, for the purposes of this study, given the nature of the NAEP data, we assume that increased use of inquiry-oriented practices by teachers is desirable and that higher scores on the scales are preferred.

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Appendix A

Polychoric Factor Analysis of Inquiry-Oriented Instruction Composite Measure

¹ Five items included in Smith and colleagues’ (2007) composite measures were not included on the 2011 NAEP’s Grade 8 science assessment teacher survey and were not included in our composite measures. Specifically, (1) how often students (a) undertook an individual/group project that took a week or more and (b) used lab notebook/journal; (2) how often teachers (a) evaluated students based on hands-on activities; and (3) how much emphasis teachers placed on (a) knowing how to communicate ideas in science effectively and (b) developing data analysis skills.

² Item was reverse coded prior to analysis.

³ Item was included on 2011 NAEP Grade 8 Science Assessment teacher survey but was unavailable on 2000 NAEP teacher survey and not included in Smith et al.’s composite measures.

Appendix B

Correlations Among Teacher-Level and School-Level Variable

Table B1. Correlations Among Teacher-Level Variables

Appendix B.2. Correlations Among School-Level Variables