Analysis of symmetrically predicted endogenous subgroups (ASPES) is an approach to assessing heterogeneity in an ITT effect from a randomized experiment when an intermediate variable (one that is measured after random assignment and before outcomes) is hypothesized to be related to the ITT effect, but is only measured in one group. For example,…

This article discusses estimation of average treatment effects for randomized controlled trials (RCTs) using grouped administrative data to help improve data access. The focus is on design-based estimators, derived using the building blocks of experiments, that are conducive to grouped data for a wide range of RCT designs, including clustered and…

Randomized controlled trials are a special case of designs using an unbiased instrument to take care of confounders even if they are unmeasured or unknown. Another example of studies using instrumental variables is the Mendelian experiment and Directed Acyclic Graphs show the power of such designs to enhance the internal validity. It is argued…