There's been some concerns about these in the past, so I thought I'd post findings here so that there might be some better understanding.
Attendance is a percentage. Specifically, your life-time attendance since the DKP was implemented, or you joined/were added to the DKP. In this way, your attendance will become harder to change over time. However, don't worry that this number isn't 100%! It's not what's used to determine "activity." We also add transactions where points are spent for items as a raid with no attendees, meaning everyone's attendance will suffer for that "raid."
Activity, on the other hand, is a very funny little function. Activity works as such. If you haven't attended anything, your activity is 10. Why? Iono. It just is. If you attended events, but none in the last 45 days, your activity is 0.
The actual number from here is a pretty confusing calculation. Suffice to say if you miss mandatory raids, it will go down and fast. If you miss raids with attendance set as "regular" then nothing will happen. You can check the different events in the DKP, and they'll be labeled as Bonus, Mandatory or Regular from there.
The exact function is: 5 + (rounded down((Mandatory raids in 45 days attended / Mandatory raids in 45 days total) * 5)) - Missed mandatory raids in 45 days + exempted mandatory raids in 5 days (capped at 3)
At the time of this post, these were calculated to be run on a weekly basis, most likely from the last time they were manually run.
Spiriel Admin replied
792 weeks ago