There is a new Best Evidence in Brief and the first study they mention surprises me. I’ll first share the insights, and than say why it surprises me:

A working paper from the National Center for Analysis of Longitudinal Data in Education Research finds evidence that teaching assistants can have positive effects on student outcomes.

Charles T. Clotfelter and colleagues examined the role of teaching assistants and other non-teaching staff in elementary schools in North Carolina to identify causal effects on students’ test scores in math and reading.

Positive effects were identified on test scores in reading, but for math, positive effects were only found for minority students’ test scores. For both reading and math, the effects on minority students’ test scores were larger than the effects on the test scores for white students.

The report also found that more teachers (and therefore smaller class sizes) had a number of positive effects on test scores, particularly for minority students, and were also associated with lower absentee rates and a lower probability of high rates on in-school suspension.

So, why does this study surprises me? Well, previous accounts showed that teaching assistants are not that positive on learning outcomes, check this talk I had with John Hattie although we discussed teaching-assistants regarding inclusive education. The last sentence is also in contradiction with the many people (cfr OECD, Hattie) that state that class size doesn’t have a big influence, although we did mention different nuances to this in our book and also this research shows nuances:

“…although some of the effects are not statistically significant. The largest and most robust effects on test scores are for minority students. For these groups, smaller class sizes at the school level are associated with higher scores in both reading and math. More teachers also lead to lower student absentee rates and a lower probability of high rates of in-school suspension.”