This paper examines the reflection problem that arises when a researcher observing the distribution of behavior in a population tries to infer whether the average behavior in some group influences the behavior of the individuals that comprise the group. It is found that inference is not possible...

A common concern of evaluation studies is to learn the distribution of outcomes when a specified treatment policy, or assignment rule, determines the treatment received by each member of a specified population. Recent studies have emphasized evaluation of policies providing the same treatment to...