Systems for determining improper assignments in statistical hypothesis testing

Described are techniques for performing statistical hypothesis experiments and determining user responses that do not match an assigned treatment. One of multiple experiment states may be assigned to a set of client devices. Response data that includes indications of the experiment state that was executed may be compared to the assigned experiment state to determine allocation matches and allocation mismatches. The allocation mismatches may be separated based on the assigned and executed experiment states to determine mismatches caused by preexisting content stored on a client device and mismatches caused by other experiment parameters.