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Using Multisite Experiments to Study Cross-Site Variation in Treatment Effects

Howard Bloom, Steve Raudenbush, Michael Weiss, & Kristin Porter

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Multisite randomized trials are experiments where individuals are randomly assigned to alternative experimental arms within each of a collection of sites (e.g., schools).  They are used to estimate impacts of educational interventions. However, little attention has been paid to using them to quantify and report cross-site impact variation. The present paper, which received the 2017 JREE Outstanding Article Award, provides a methodology that can help to fill this gap.

Why and how is knowledge about cross-site impact variation important?

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The Implications of Teacher Selection and the Teacher Effect in Individually Randomized Group Treatment Trials

Michael Weiss

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Beware! Teacher effects could mess up your individually randomized trial! Or such is the message of this paper focusing on what happens if you have individual randomization, but teachers are not randomly assigned to experimental groups.

The key idea is that if your experimental groups are systematically different in teacher quality, you will be estimating a combined impact of getting a good/bad teacher on top of the impact of your intervention.

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Effect Sizes Larger in Developer-Commissioned Studies than in Independent Studies

Rebecca Wolf, Jennifer Morrison, Amanda Inns, Robert Slavin, and Kelsey Risman

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Rigorous evidence of program effectiveness has become increasingly important with the 2015 passage of the Every Student Succeeds Act (ESSA). One question that has not yet been addressed is whether findings from program evaluations carried out or commissioned by developers are as trustworthy as those identified in studies by independent third parties. Using study data from the What Works Clearinghouse, we found evidence of a “developer effect,” where program evaluations carried out or commissioned by developers produced average effect sizes that were substantially larger than those identified in evaluations conducted by independent parties.

Why is it important to accurately determine the effect sizes of an educational program?

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