Reporting on Absent Members
Obtaining a list of members who did not attend an activity is a little tricky. If you run an activity report that includes attendance, it can only show members who did attend, not members who did not.
The solution is to run a membership report (like the Contact list, Roster, Directory, or any user-defined report based on membership data) or a search on the Membership List, and use a special criteria Field Name called "Absent from Activity".
This criteria set will find any members over age 50 who did not attend (were absent from) the activity.