Home > Publications . Search All . Browse All . Country . Browse PSC Pubs . PSC Report Series

PSC In The News

RSS Feed icon

Work by Bailey and Dynarski cited in NYT piece on income inequality

Pfeffer says housing bubble masked decade-long growth in household net worth inequality

House, Burgard, Schoeni et al find that unemployment and recession have contrasting effects on mortality risk

Highlights

Jeff Morenoff makes Reuters' Highly Cited Researchers list for 2014

Susan Murphy named Distinguished University Professor

Sarah Burgard and former PSC trainee Jennifer Ailshire win ASA award for paper

James Jackson to be appointed to NSF's National Science Board

Next Brown Bag


PSC Brown Bags will return in the fall

Ben Hansen photo

Covariate balance in simple, stratified and clustered comparative studies

Publication Abstract

Hansen, Ben, and J. Bowers. 2008. "Covariate balance in simple, stratified and clustered comparative studies." Statistical Science, 23(2): 219-236.

In randomized experiments, treatment and control groups should be roughly the same-balanced-in their distributions of pretreatment variables. But how nearly so? Can descriptive comparisons meaningfully be paired with significance tests? If so, should there be several such tests, one for each pretreatment variable, or should there be a single, omnibus test? Could such a test be engineered to give easily computed p-values that are reliable in samples of moderate size, or would simulation be needed for reliable calibration? What new concerns are introduced by random assignment of clusters? Which tests of balance would be optimal? To address these questions, Fisher's randomization inference is applied to the question of balance. Its application suggests the reversal of published conclusions about two studies, one clinical and the other a field experiment in political participation.

DOI:10.1214/08-sts254 (Full Text)

Browse | Search : All Pubs | Next