treatments are conditionally randomly assigned and the controls are sufficiently flexible to avoid omitted variables bias … treatments. Thus, recent concerns about heterogeneity-induced bias in regressions leveraging potential outcome restrictions (e … contamination bias and propose a new class of efficient estimators of weighted average effects that avoid bias. In a re-analysis of …

make no difference. However, the small sample properties can differ. We explore small sample power and estimation bias both …) in the auxiliary model. We find that both power and bias are similar when the number of variables used is the same …. Raising the number of variables lowers the bias but may also raise the power unacceptably because it lowers the chances of …

Science rests upon the reliability of peer review. This paper suggests a way to test for bias. It is able to avoid the … data from the field of economics. No scientific bias or favoritism is found (although the Journal of Political Economy …