There is no way to find if all instances of an event were relatively spaced within a specific time frame. For example: no more than 10 weeks elapsed between any two blood monitoring events. It was suggested to add a "count unique outside" operator. It would act similar to "count unique" operator proposed in the QDM-6, but instead finds items outside of given period of time.

Note that "count unique outside" may not be the best wording to handle this issue. Also maybe related to finding the closest events.