A Finite Population Likelihood Ratio Test of the Sharp Null Hypothesis for Compliers

In a randomized experiment with noncompliance, scientific interest is often in testing whether the treatment exposure X has an effect on the final outcome Y. We propose a finite-population significance test of the sharp null hypothesis that X has no effect on Y, within the principal stratum of Compliers, using a generalized likelihood ratio test. We present a new algorithm that solves the corresponding integer programs.