I’ve lauded Bruce Baker’s blog once already, but day by day I’m becoming an even more devoted follower of his wit and his brilliant exposés of fallacious research, bogus claims, and shallow thinking. I’ve learned/confirmed so much by subscribing to School Finance 101, particularly about value added models and student growth percentile models, as Dr. Baker reexamines the research on these topics and highlights the shortcomings and the unintended consequences of using these measures in states all over the country.
I’m very interested in his work on student growth percentiles, first created by Damien Betebrenner at the National Center for the Improvement of Educational Assessment, www.nciea.org. First used in Colorado, and now spreading to Massachusetts, New Jersey and New York, the proponents of SGPs suggest they fix the problems inherent in value added measures. Baker emphatically says not so, and uses the writings of the fathers of SGPs to highlight how SGPs are being misused.
To get up to speed on VAMs and SGPs and their problems as Baker sees them, go through the blog references found in his Value Added Teacher Evaluation category here, and as you read the articles, click on through to the links within each one. You’ll get quite a wonderful look at the limitations of these statistical models as they relate to teacher evaluation. Baker also takes on state education officials in several states, including Colorado, New Jersey and New York, with his irrevent commentary.
Of particular interest for New Yorkers is his analysis of the preliminary technical reports on the results of NY’s first SGP assessment results. This analysis can be seen in the entry entitled “AIR Pollution in NY State…” He offers graphs showing how factors that cannot be attributed to teachers have an effect on the patterns of SGP scores–students in low income schools generally underperform students in higher income schools, as one already knows, but the SGPs of these students also lag behind higher income schools. This demonstrates that SGPs do not, in fact, account for effects of peer groups, of school effects, or of poverty, as some suggest.
Read Baker and weep about how assessments are regularly being misused by people who should know better,