Differences In DC Teacher Evaluation Ratings By School Poverty
In a previous post, I discussed simple data from the District of Columbia Public Schools (DCPS) on teacher turnover in high- versus lower-poverty schools. In that same report, which was issued by the D.C. Auditor and included, among other things, descriptive analyses by the excellent researchers from Mathematica, there is another very interesting table showing the evaluation ratings of DC teachers in 2010-11 by school poverty (and, indeed, DC officials deserve credit for making these kinds of data available to the public, as this is not the case in many other states).
DCPS’ well-known evaluation system (called IMPACT) varies between teachers in tested versus non-tested grades, but the final ratings are a weighted average of several components, including: the teaching and learning framework (classroom observations); commitment to the school community (attendance at meetings, mentoring, PD, etc.); schoolwide value-added; teacher-assessed student achievement data (local assessments); core professionalism (absences, etc.); and individual value-added (tested teachers only).
The table I want to discuss is on page 43 of the Auditor’s report, and it shows average IMPACT scores for each component and overall for teachers in high-poverty schools (80-100 percent free/reduced-price lunch), medium poverty schools (60-80 percent) and low-poverty schools (less than 60 percent). It is pasted below.
In short, this table suggests that there is a rather substantial discrepancy in IMPACT results between teachers in low-poverty schools versus their counterparts in medium- and high-poverty schools.
Specifically, you’ll notice that almost 30 percent of teachers in low-poverty schools receive the highest rating (“highly effective”), compared with just 7-10 percent in the other categories. In addition, just over seven percent of teachers in low-poverty schools receive one of the two lowest ratings (“minimally effective” or “ineffective,” both of which may result in dismissal), versus 18-21 percent in the medium- and high-poverty schools.
So, the relationship between school poverty and IMPACT ratings may not be linear, as the distributions for medium- and high-poverty schools are quite similar. Nevertheless, it seems very clear that IMPACT results are generally better among teachers in schools serving lower proportions of poor students (i.e., students eligible for subsidized lunch), and that the discrepancies are quite large.
One question is why these differences, which have been found elsewhere in both test-based and non-test-basedmeasures, arise.
Broadly speaking, there are two possible explanations (and they are not mutually exclusive). The first, put crudely, is Shanker Blog » Differences In DC Teacher Evaluation Ratings By School Poverty: