Which of the following must be undertaken when the treatment and control groups differ with regard to some independent variable, X1.
A) Run an intention-to-treat analysis
B) Run a 2SLS model where the instrument is the random assignment
C) Use multivariate OLS and control for X1.
D) Restart the experiment and pick a new randomized sample.

Question

Quizplus · Accepted Answer

When the treatment and control groups differ with regard to some independent variable, X1, the best approach is to use multivariate OLS and control for X1. This allows for the statistical control of confounding variables, which can help to isolate the effect of the treatment on the outcome variable. Running an intention-to-treat analysis is not useful in this situation as it does not address the issue of confounding variables. A 2SLS model with random assignment as the instrument is not appropriate here since the groups are already randomized. Restarting the experiment and picking a new randomized sample is not practical or necessary if statistical control can be achieved through multivariate OLS.

Which of the Following Must Be Undertaken When the Treatment