Melissa A. Clark and others report,

In 2010, Teach For America (TFA) launched a major expansion effort, funded in part by a five-year Investing in Innovation (i3) scale-up grant of $50 million from the U.S. Department of Education. This study examines the effectiveness of TFA elementary school teachers in the second year of the scaleup, relative to other teachers in the same grades and schools. The study found that, on average, TFA corps members hired in the first two years of the scale-up period were as effective as other teachers in the same high-poverty schools in both reading and math. Although TFA teachers in lower elementary grades (prekindergarten through grade 2) had a positive, statistically significant effect on students’ reading achievement relative to other teachers in the same schools, this was not true for TFA teachers in upper elementary grades (3 through 5) in reading, or for any grade level in math.

Pointer from Jason Richwine, who notes

On the bright side, TFA teachers appear to be at least as effective as regular teachers when it comes to teaching reading and math to elementary students. The fact that TFA requires only a five-week crash course in pedagogy — rather than traditional teacher certification — is another reason to question the value of an education degree.

Of course, this is consistent with the Null Hypothesis, as applied to teacher education. Actually, if you believe the Null Hypothesis only applies to teacher education, then you would expect the TFA teachers, who presumably have higher native ability, to perform better than typical teachers. However, then you run into the Null Hypothesis for education in general.