I attended a small rally for open government and transparency this morning at the Wilson Building in downtown DC, sponsored by the Washington Teachers’ Union.
The issue is a move to make it so that no one — not even the WTU, which is the bargaining agent for all DCPS teachers — would be able to see any teacher evaluation data, even with names or other identifying information redacted. To be sure, the Union is not interested in having names and scores of teachers printed in the Washington Post or put on-line. However, Using leaked data from DCPS’s first year of the IMPACT teacher evaluation system, I have shown on this blog that the evaluation system is basically invalid, since there is only a very low correlation between classroom observation scores and “value-added” scores computed by an incomprehensible “black box” algorithm whose details teachers are not permitted to see or examine.
If we had more data on these invalid scores, we would probably discover that, as in New York City, the “Value-Added” scores jump around wildly from year to year for any given teacher, even if they are teaching the exact same subject and grade level and at the same school, teaching very similar kids. (R-Squared in NYC was less than 0.1, which means essentially no correlation at all! In DC, r-squared correlation between classroom observation scores and “value-added” scores was about 0.13, also quite low.)
That’s me in the back holding the handmade sign with graphs I made.