# Serial up-voting reversed?

Today$^{[2]}$ I came across some MSE user profile and noticed that (s)he lost almost $10$k reputation on single day the reason being Serial up-voting reversed

AFAIK This faq post on meta says

Every night around $03:00$ UTC, a voting fraud detection script is run that looks for patterns

And it is very well known that a user can earn at most $200$ reputation (only from up-votes) and then it's obvious$^{[1]}$ that one cannot earn ~$10000$ reputation on one single day and I think that no matter what kind of fraud occurs, it's effect(reputation change) will be reversed within $24$ hours. Then it is impossible that one can could lose ~$10000$ rep due to reversal of serial up-voting.

Now that I have eliminated the impossible, whatever remains, however improbable, must be the truth

Then, Is this some kind of undocumented-feature? Could someone here explain this (with some reference)?

Thanks!

$[1]$ I have no citations for this $[2]$ Please excuse my English

• In addition to the daily script, there are also scripts checking for long-running voting patterns, and from time to time a developer looks at the database personally when there are sufficient grounds to do so. This was evidently not the daily script for short series, this was one of the bigger guns. I don't know whether automatic or manual, however (and I think nobody is going to tell us) – Daniel Fischer Dec 6 '14 at 14:49
• It is not quite clear what exactly you are asking; the FAQ post you link to even suggests that more than one day can be affacted. Note, eg, (my emphasis) 'When the system detects this pattern, all of the votes cast from that user to the user affected are reversed[...]' and 'Whenever serial voting gets reversed, all days involved in the serial voting will be recalculated as if the serial votes had never happened,[...]' Anyway, if you check the right things on the profile you mention you can note easily that there must have been a quite massive number of accounts involved. – quid Dec 6 '14 at 15:51
• I don't get the number. Reputation from upvotes comes in quanta of +5 and +10. How can it be summed up to get 10599? – d80d2729a352b1366139fc119d3345 Dec 6 '14 at 16:34
• @HatMan ~$10000\neq10599$? – Aditya Hase Dec 6 '14 at 16:35
• @Integrator Doesn't the number to left correspond to the action on right? – d80d2729a352b1366139fc119d3345 Dec 6 '14 at 16:39
• @HatMan following the link you get "The value of the reversal could be anything, as it is the combined amount of all the votes being reversed (up and down, although most serial voting occurs in one direction). If you had reached the reputation cap, the value may show up as blank if none of the votes being reversed actually affected your reputation on that day." – quid Dec 6 '14 at 16:40
• @quid But it is labelled as serial upvoting rather than serial voting. – d80d2729a352b1366139fc119d3345 Dec 6 '14 at 16:46
• @HatMan Even if only upvotes are involved this would be possibly due to the 200 points cap. It might also be an imprecission of the documentation, or it might also be that since upvotes triggered it the process is referred to in this way while then all kinds of votes are affected. – quid Dec 6 '14 at 17:04