Evidence for the Need to More Closely Examine School Effects in Value-Added Modeling and Related Accountability Policies

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Value-added approaches for attributing student growth to teachers often use weighted estimates of building-level factors based on “typical” schools to represent a range of community, school, and other variables related to teacher and student work that are not easily measured directly. This study examines whether such estimates are likely to be accurate in “outlier” schools where building-level characteristics, such as demographics and faculty qualifications, are at the outer edges of the distribution of schools on which the “typical school” estimates are based. We examined whether building-level factors correlate with grade-level ratings in one of the most widely used approaches to value-added modeling, thus impacting interpretation of value-added ratings of teachers. Urban schools may be particularly affected by findings that reliable interpretation of a model using typical school estimates is affected by aspects of the school, even when using a weighted model. More correlations were found than would be expected by chance, many fairly large. Correlations tend to cluster around particular variables, possibly an effect of system accommodations for demographic or economic factors. A greater range and number of correlations were found for mathematics than reading. Finally, correlations and strength of relationships increase with grade level.