How many NYC are arbitrarily punished by the VAM? About 578 per year.
There’s been an important update in the thought experiment I started yesterday. Namely, a reader (revuluri) has provided me with a link to show how many teachers are considered “ineffective,” which was my shorthand for scoring either third or fourth in the four categories.
According to page 5 of this document, that percentage was 16% in 2011-2012, 17% in 2012-2013, and 16% in 2013-2014. We’ll take this to mean that the true cutoff is about 16.3%. Using my formula from yesterday, that means that after 4 years, about
or 12.7% of teachers going up for tenure in the new system will be arbitrarily denied tenure based only on their VAM score.
How many people is that in a given year? Well, this document explains that in 2000, 9,000 teachers were hired and in 2008, 6,000 teachers were hired. I’ll assume my best guess for “teachers hired” in a given year is something between those two numbers, but I’ll also assume it’s closer to the latter since it is more recent information. Say 7,000 new teachers per year.
Of course, not all of them go up for tenure. There’s attrition. Say 35% of those teachers leave before the tenure decision is made (also guessing from this document). That leave us with about 4,550 teachers going up for tenure each year, and 12.7% of them is 578 people.
So, according to my crude estimates, about 578 people will be denied tenure simply based on this random number generator we call VAM. And as my reader said, this says nothing about the hard-to-measure damage done to all the good teachers trying to teach their kids but having to deal with this standardized testing nonsense. It’s a wonder anyone is willing to work here.
Please comment if you have updated numbers for anything here.