The Friedman Foundation for Educational Choice

Advancing Milton and Rose D. Friedman's Vision of School Choice for All Children

Gold Standard Studies

Evaluating School Choice Programs

The gold standard methodology in the social sciences is called “random assignment.” This method allows researchers to isolate the effects of vouchers or scholarships from other student characteristics. Students who apply for a voucher enter randomized lotteries to determine who will receive the voucher and who will remain in a public school; this allows researchers to track very similar "treatment" and "control" groups, just like in medical trials. The following study citations and brief summaries are listed in chronological order, from most recent to oldest

Study Citations and Findings

Matthew M. Chingos and Paul E. Peterson, The Effects of School Vouchers on College Enrollment: Experimental Evidence from New York City, Brookings Institution, 2012.

Findings New York, NY—Black students using vouchers to attend private school attended college within three years of expected high school graduation at a rate 8.7 percentage points higher than the control group, and full-time college attendance rates were 8 percentage points higher. The offer of a voucher to black students resulted in their college attendance rate for a selective four-year college being more than double the control group’s rate (6.9 percent vs. 3.0 percent, respectively).

Hui Jin, John Barnard, and Donald B. Rubin, “A Modified General Location Model for Noncompliance with Missing Data: Revisiting the New York City School Choice Scholarship Program using Principal Stratification,” Journal of Educational and Behavioral Statistics, April 2010.

Findings New York, NY—Using alternative methods, this study confirms the 2003 finding that, after one year, voucher students had math scores 5 percentile points higher than the control group.

Patrick J. Wolf, Babette Gutmann, Michael Puma, Brian Kisida, Lou Rizzo, Nada Eissa, and Matthew Carr, Evaluation of the D.C. Opportunity Scholarship Program: Final Report, U.S. Department of Education, National Center for Education Evaluation and Regional Assistance, June 2010.

Findings Washington D.C.—The students offered vouchers graduated from high school at a rate 12 percentage points higher (82 percent) than students in the control group (70 percent), an impact that was statistically significant at the highest level. Students in three of six subgroups tested showed significant reading gains because of the voucher offer after four or more years. Overall, reading and math gains from the program were not statistically significant at the 95 percent confidence level, but overall reading gains were significant at the 90 percent confidence level. Parents remained more satisfied with their child's school and viewed it as safer if offered a voucher, even though students had similar views of school satisfaction and safety whether in the treatment or control group.

Joshua M. Cowen, “School Choice as a Latent Variable: Estimating ‘Complier Average Causal Effect’ of Vouchers in Charlotte,” Policy Studies Journal, May 2008.

Findings Charlotte, NC—After one year, voucher students had reading scores 8 percentile points higher than the control group and math scores 7 points higher.

Alan B. Krueger and Pei Zhu, “Another Look at the New York City School Voucher Experiment,” American Behavioral Scientist, January 2004.

Findings New York, NY—The voucher students had higher scores, but the results did not achieve statistical significance. Subsequent analysis has demonstrated that this occurred because the study used inappropriate research methods that violate the norms of the scientific community; if legitimate methods are used, the positive results for vouchers become significant.

John Barnard, Constantine E. Frangakis, Jennifer L. Hill, and Donald B. Rubin, “Principal Stratification Approach to Broken Randomized Experiments: A Case Study of School Choice Vouchers in New York City,” Journal of the American Statistical Association, June 2003.

Findings New York, NY—After one year, voucher students had math scores 5 percentile points higher than the control group.

William G. Howell and Paul E. Peterson, The Education Gap: Vouchers and Urban Schools, Brookings Institution, 2002, revised 2006.

Findings New York, NY—After three years, black voucher students had combined reading and math scores 9 percentile points higher than the control group.

William G. Howell and Paul E. Peterson, The Education Gap: Vouchers and Urban Schools, Brookings Institution, 2002, revised 2006.

Findings Washington D.C.—After two years, black voucher students had combined reading and math scores 9 percentile points higher than the control group, and all voucher students had combined reading and math scores 7.5 percentile points higher than the control group.

William G. Howell and Paul E. Peterson, The Education Gap: Vouchers and Urban Schools, Brookings Institution, 2002, revised 2006.

Findings Dayton, OH—After two years, black voucher students had combined reading and math scores 6.5 percentile points higher than the control group.

Jay P. Greene, “Vouchers in Charlotte,” Education Next, Summer 2001.

Findings Charlotte, NC—After one year, voucher students had combined reading and math scores 6 percentile points higher than the control group.

Jay P. Greene, Paul E. Peterson, and Jiangtao Du, “School Choice in Milwaukee: A Randomized Experiment,” in Learning From School Choice, eds. Paul Peterson and Bryan Hassel, Brookings Institution, 1998, pp. 335-56.

Findings Milwaukee, WI—After four years, voucher students had reading scores 6 Normal Curve Equivalent (NCE) points higher than the control group, and math scores 11 points higher. NCE points are similar to percentile points.

Cecilia E. Rouse, “Private School Vouchers and Student Achievement: An Evaluation of the Milwaukee Parental Choice Program,” Quarterly Journal of Economics, May 1998.

Findings Milwaukee, WI—After four years, voucher students had math scores 8 NCE points higher than the control group. NCE points are similar to percentile points.