|Read a Post for Trends of School Effects on Student Achievement: Evidence from NLS:72, HSB:82, and NELS:92|
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about the contamination effect of student level prior achievement
|Posted By: Bo Yan on December 12, 2008|
|It is interesting that the author mentioned "the use of sophomore achievement as an adjustment of prior student ability is hardly the most appropriate pre-school measure in a school effects study because it can be contaminated with school effects, and its inclusion as a covariate would most likely underestimate the cumulative nature of school effects". I wonder theoretically what the machanism of the contamination effect is. |
On the other hand, the results from Table 5. do tell us the effect of school for that particular one school year after factoring in student prior ability. Then, the question is whether this effect can be consistently observed in other school years.