How do clinical trials validate medication taking behavior?

Did the clinical trial use the Morisky? The Morisky Medication Adherence Scale is a simple and effective tool to address medication non-adherence in clinical trials. With an Internal Consistency
Cronbach's alpha .83, Sensitivity 93%, and Specificity 57%. It has been validated by clinicians and health professionals for different chronic conditions. It has been translated in over 90 languages. It can be administered electronically or at each office visit for long-term consistent evaluation.

The MMAS-8 has undergone numerous levels of validation, including construct validation, discriminant validation, convergent validity with the MMAS scales, and the closest type of validation which mimics the "gold standard", criterion-related validity. The self-reported MMAS-8 agreed with physiological outcome measures such as BP control, HgA1c levels, GFR rates, HDL/LDL ratios, viral load levels, topical skin disorders, etc.