Hi William,
There are several well-known deficiencies in current data standards due to a conflict between general scientific principles vs. particular practical needs.
Lack of standardization in Disposition data is one of examples. DS is some sort of “generic” domain. It was developed to handle all possible Study Disposition data and all possible cases.
Yes, Disposition Event Start Date may be not applicable sometimes. However this information is heavily used by FDA reviewers to estimate drug Efficacy and Safety as well as general Data Quality. E.g.,
There are many standard reports based on DSSTDTC variable. Independent reviewers (e.g., FDA) will try to analyze your Disposition timing info regardless of your company common data collection practice.
Regards,
Sergiy