This study by Jesse Wood et al. focuses on a very important question: are the methods used to teach students with disabilities effective and inclusive for all students? While you might be inclined to say yes straight away, I did mention already examples where this may not be the case. In this study also, the researchers found results that show it’s more complicated:

They found that some of the best-performing teachers for students without disabilities have lower value-added scores for students with disabilities. Similarly, they noted that top-performing teachers for students with disabilities have lower value-added scores for students without disabilities. This means that some students who may appear to be matched with a high-quality teacher could actually be better off with other teachers. (source: the press release)

Or more elaborated in the article:

First, we establish that teachers are differentially effective at supporting SWDs. Teachers who are effective at teaching non-SWDs are not synonymous with teachers who are best able to support SWDs. Indeed, we show that a non-negligible share of the top-performing teachers for non-SWDs have relatively poor performance for SWDs (as measured by VAMs). Second, there does not seem to be any relationship between either SWD or non-SWD VAMs and teacher education, experience, or credentials. We started with the assumption that it may be helpful for principals to know which teachers have an advantage in teaching specific student groups. Unfortunately, our results suggest that observable teacher characteristics cannot meaningfully inform principals about teacher VAMs for each student group.

In line with this last remark, sadly, the study, published in the journal Educational Evaluation and Policy Analysis, doesn’t answer the question of what makes methods work better for one group of students than for another.

Abstract of the study:

The success of students with disabilities (SWDs) depends on access to high-quality general education teachers. Yet, teacher value-added measures (VAMs) generally fail to distinguish between effectiveness in educating students with or without disabilities. Using data from the Los Angeles Unified School District, we create two VAMs: one focusing on teachers’ effectiveness for SWDs and one for non-SWDs. We find that many top-performing teachers for non-SWDs have relatively lower VAMs for SWDs and vice versa, and that on average SWDs have teachers with lower scores in both VAMs than non-SWDs. Overall, SWD-specific VAMs may be more suitable for identifying which teachers have a history of effectiveness with SWDs and could play a role in informing student assignment to teachers.