Tuesday, February 12, 2013

CREDO issues Charter School Growth and Replication Report

CREDO came out with another study of charter schools, entitled Charter School Growth and Replication (the press release, executive summary, and full report are here). This is a follow-up from their earlier National Charter School Study (posted on the same web site).

I’m somewhat skeptical of their methodology, especially the use of “virtual twins” (see the Center for Education Reform’s critique below), but I don’t dismiss it entirely – in fact, I think there are important lessons to be learned from their studies.

I want to highlight the first two (of 13) conclusions from the executive summary:

1. It is possible to organize a school to be excellent on Day One. New schools do not universally struggle in their early years; in fact, a surprising proportion in each gradespan produce strong academic progress from the start. Interestingly, the attributes of a school -- urban, high poverty or high minority -- have no relation to the performance of the school. Based on the evidence, there appears to be no structural "new school" phenomenon of wobbly performance for several years.

2. The initial signals of performance are predictive of later performance. We use the distribution of schools' value add for all schools in each of our included states, divided into quintiles, to map an individual charter school as being low performing (Quintile 1) or high performing (Quintile 5) or in-between. For middle and high schools, we can obtain an initial signal of performance at the end of the first year for a new school, since their enrolled students have prior test scores. The earliest we can measure an elementary school's quality is in the second year (since it takes two years to create a growth measure.)

Taking the first available performance measure and using it to predict one-year increments going forward, 80 percent of schools in the bottom quintiles of performance remain low performers through their fifth year. Additionally, 94 percent of schools that begin in the top quintile remain there over time.

If we wait until the third year to start the predictions (i.e. use two growth periods as the basis of setting the initial performance for the subsequent conditional probabilities), the patterns are even stronger: 89 percent of low performing schools remain low performing and 97 percent of all the high flyers persist at the top of the distribution.

Folks, this is REALLY important – and highly consistent with my observations. Schools that start sucky, stay sucky, and schools that start good stay good, with very few (albeit often well publicized) exceptions. The implications of this finding are very powerful for everyone involved in the charter school movement. We tend to apply the 80/20 rule in a negative way: we piss away 80% of our resources trying to fix the suckiest 20% of schools within networks, cities, and states. What the CREDO study (and plain common sense) says is the opposite: we should be spending 80% of our resources helping the TOP 20% of schools expand and replicate. And we should quickly (within three years) pull the plug on the bottom 20%.

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