Magically lost rep points. Possible causes?

Question

When I logged in today on SO I noticed I had lost ~25–30 rep points somehow. Looking through my history I couldn't really see any changes in votes. What could be the cause of this? Is there a way to identify the root cause for loss in points?

Edit: As a natural follow up to my original question, will SO add some kind of mechanism that'll permit us to see where the loss in rep points came from? I'm thinking something like a notification + another page for this under our profile would work. It would help make it easier to account.

Right now we can only go through our history page of our post and it's almost impossible to discern just from looking at that.

Answer 1

This is probably a recalc of your reputation.

When the automatic reputation recalc happens, it runs through the entire audit and work out your new correct reputation score.

On Stackoverflow sites, off-topic, subjective/argumentative, migrated out and duplicate questions are cleaned up periodically as part of regular housekeeping. Most of that means deletion, merging in the case of duplicates. Your new reputation is far lower than you expected now probably because of deleted questions/answers you've posted to are no longer "there" to account the reputation for.

You can check the following posts on the primary meta about this issue:

• What can cause Actual rep to differ from Shown rep?
• Why would I lose rep overnight - could it be related to multiple upvotes from a colleague?
• rep-recalc tag

Answer 2

It could have been answers being unaccepted and/or votes being removed.

Answer 3

It could be from when the reputation was recalculated. They changed questions to be only worth 5 points instead of 10. So any rep gained from questions was cut in half. I do not recall the exact date this happened.