DRAFT: DO NOT QUOTE OR CITE DRAFT: DO NOT QUOTE OR CITE 1 Designing Probability Samples to Study Treatment Effect Heterogeneity Elizabeth Tipton Teachers College, Columbia University David S. Yeager University of Texas at Austin Ronaldo Iachan ICF International Barbara Schneider Michigan State University DRAFT: November 30, 2016 (Comments welcome) To appear in: Lavrakas, P.J. (Ed.). Experimental Methods in Survey Research: Techniques that Combine Random Sampling with Random Assignment. New York: NY: Wiley. Author Note Writing of this chapter was supported by the Spencer Foundation and, for the second author, by the Raikes Foundation, the William T. Grant Foundation, the National Institute of Child Health and Human Development under award number R01HD084772, and a fellowship from the Center for Advanced Study in the Behavioral Sciences (CASBS). The National Study of Learning Mindsets (PI: Yeager; Co-Is: Dweck, Walton, Crosnoe, Schneider, & Muller) was made possible through methods and data systems created by the Project for Education Research That Scales (PERTS), data collection carried out by ICF International, and received support from the Raikes Foundation, the William T. Grant Foundation, the Spencer Foundation, the Bezos Family Foundation, the Character Lab, the Houston Endowment, Angela Duckworth (personal gift), and the President and Dean of Humanities and Social Sciences at Stanford University. Please address correspondence to Elizabeth Tipton, 525 W 120 th Street, Box 118, New York, NY 10027 (email: tipton@tc.columbia.edu) or to David S. Yeager, 108 E. Dean Keeton, Austin, TX, 78712 (email: dyeager@utexas.edu).