Replication data for: Reproduction Compendium for: `Making Effects Manifest in Randomized Experiments'

After data collection, concern may focus on random imbalance between treatment groups on substantively important variables. Pursuit of these three goals --- enhanced precision, understanding treatment effect heterogeneity, and imbalance adjustment --- requires background information about experimental units.

For example, one may group similar observations on the basis of such variables and then assign treatment within those blocks. Use of covariates after data have been collected raises extra concerns and requires special justification. For example standard regression tables only approximate the statistical inference that experimentalists desire.