Hi Mark,

So it sounds like you might want to use a visit-based study instead of a time-based one.

Since visits are organized by sequences rather than date ranges, this would fit your needs best due to not knowing the date of when someone's Day was.

Take a look at our comparison page regarding using Visits vs Timepoints for more information.

https://www.labkey.org/wiki/home/Documentation/page.view?name=visits

Let us know if you have any further questions.

Regards,

Jon