TY  - JOUR
AU  - Ding,Weili
AU  - Lehrer,Steven F.
TI  - Estimating Treatment Effects from Contaminated Multi-Period Education Experiments: The Dynamic Impacts of Class Size Reductions
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 15200
PY  - 2009
Y2  - August 2009
UR  - http://www.nber.org/papers/w15200
L1  - http://www.nber.org/papers/w15200.pdf
N1  - Author contact info:
Weili Ding
Queens University
138 Union Street
Sutherland Hall
Kingston
Ontario  K7L 3N6
Canada
Tel: 613-533-6000x78784
Fax: 613-533-2135
E-Mail: dingw@queensu.ca

Steven F. Lehrer
School of Policy Studies
and Department of Economics
Queen's University
Kingston, ON K7L 3N6
CANADA
Tel: 613/533-6692
Fax: 613/533-2135
E-Mail: lehrers@post.queensu.ca
AB  - This paper introduces an empirical strategy to estimate dynamic treatment effects in randomized trials that provide treatment in multiple stages and in which various noncompliance problems arise such as attrition and selective transitions between treatment and control groups. Our approach is applied to the highly influential four year randomized class size study, Project STAR. We find benefits from attending small class in all cognitive subject areas in kindergarten and the first grade. We do not find any statistically significant dynamic benefits from continuous treatment versus never attending small classes following grade one. Finally, statistical tests support accounting for both selective attrition and noncompliance with treatment assignment.
ER  -