What is the reasoning behind the reputation cap?

Question

There has been a lot of talk about the daily reputation cap and what counts and what doesn't count and so on. But why is there a cap at all? I've seen lots of questions about whether the cap number should be changed, or whether certain things should or should not apply to the cap, but I've never seen any reasoning behind why it exists in the first place.

If I write a great answer to something and get 30 upvotes in a day, why should I be deprived of 100 reputation points? What is the difference between getting 30 upvotes today and getting fifteen yesterday and fifteen today?

Answer 1

It stops the site from being gamed

A user like Jon Skeet will gain 1000+ points in an hour if this didn't exist for example. Jon objects to the cap himself for other reasons. PS: I am using Jon as an example that we all know

It is to level the playing field

It allows for others that won't gain reputation as quickly not to fall behind. Also considering that the reputation is based on how much you are trusted, it prevents users from gaining abilities without having spent enough time on the site to understand how it works. I would not want someone who has been on the site for 2 days to suddenly have the ability to close questions or edit my posts, if he hasn't had time to understand the nature of the sites.

_{The latter unfortunately has been proven to not work so well, some users still don't understand SO after a year.}

Courtesy of AnonJr:

A better example of gaming is posting dozens of (generally poor quality) questions in rapid succession and rapidly gaining rep through typical drive-by voting and/or sympathy voting. (I'm all about voting questions up when they're good, but some questions just seem to get votes for no apparent reason...) Since rep is a measure of trust, this type of rep-farming could garner enough rep for someone who is most likely not trustworthy to do things that they probably ought not to be able to do. (IIRC that was listed in a blog post/meta topic related to the caps)

Answer 2

A major reason for the rep cap is to get people to come back daily. If you miss a day, you cannot make back that rep you might have gained on that day, so it increases user participation. Further, you can't simply participate once a month for a day or two and get thousands of rep.

Far from preventing or limiting addiction, it feeds the addiction by forcing users to come back every day to get their hit.

It is, quite simply, a feature designed to grow the community by encouraging frequent small amounts of participation, rather than infrequent binges.

Answer 3

It's about Trust.

The system learns to trust you based on your reputation, and gives you new abilities as your rep increases. Part of the trust relationship you develop is not just reputation, but also time: that you've used the site over a period of time, and over that period you should come to understand the community and accepted procedures for how it operates.

So the reason the reputation threshold for certain abilities is set at a particular level is because, thanks to the daily cap, the system can assume that even a well-qualified user who hits the cap every day from day zero has spent at least a certain number of days actively using the site. A particular threshold choice equates to at least certain number of days actively using the site.

For example, vote to close at 3000 means you've actively used the site on at least 15 days (accepted answers aside) — hopefully long enough to understand what closing a question really means. It gives the community a chance to assimilate the user.

It's not fool-proof. If you're Alan Kay, for example, you could post twice, come back a year later, and find you've earned quite a few privileges. But it's a pretty good measure.

Answer 4

Addiction.

I'm not sure if Jeff has done this intentionally but it has a major role in having resources (procrastinating programmers) available on a regular basis and making it a habit for users to come and answer questions everyday rather than having irregular bursts of answers some of the time and a bunch of unanswered questions other times.

Answer 5

To control your addiction.

If you reach the rep cap it is time to return to your real life. It works for me. And I really think it is a good thing. If we would not have it some people would just go on and on and maybe could not stop chasing that rep all the time.

Answer 6

I've only recently started hitting 200 rep per day on a semi-regular basis (on rpg.se), and it seems to me the cap has the following benefits, in particular on a site with relatively small active membership:

• It stops certain individuals from answering too many questions, as they are likely to stop answering once their daily cap has been reached.
• Conversely this encourages less active users to get involved by answering questions once the more active users have eased off.
• It encourages people to do other things once their cap has been reached, like editing questions and answers, adding comments and flags.

All three of these things contribute to the overall quality of a small stack.

Answer 7

Due to the Bike Shed Problem answers to easy questions tend to get more votes since more people are able to recognize the correct answer when they see it. Without the rep cap those that answered simple questions would gain rep a lot faster than those who answered an equal amount of difficult questions.

Answer 8

For most users, most of the time they only hit the rep cap when a question or answer they have posted appears on the Hot Network Questions list.

Although not originally designed for this reason (as SOLO's answer explains), the rep cap serves as an important mitigating force against the worst side effects of the HNQ, namely that very quickly but for a limited time the voting on a question is driven by users who are not familiar with the site in question.

Not all questions on the HNQ adhere to their site specific rules, and many get closed, but after the 'damage' has already been done. I put damage there in quotes because it's entirely legitimate for the questions to be asked, answered, and voted on, and most questions which do get closed have votes and answers. Closed HNQ questions are not normally deleted if they were asked in good faith. The HNQ just amplifies activity on its questions in a semi-artificial manner.

The rep cap means that users' contributions to the sites still get recognised and rewarded, but in order to gain community moderation privileges users need ongoing contributions which are positively accepted and voted on by the site regulars, not HNQ visitors.

Answer 9

The intention is to get the user to come back to the site daily, for ever.

A site is (also) measured by the number of users. It makes a difference having 50k users for 20 years and more, vs having 100k users for 2 days then just 100 thereafter.

It's well-researched, that games implement such features to keep the users on the site; a wheel that you can spin once a day, a scratchcard that is re-available after six hours, etc etc. For it to work, what is lost must not be recoverable (ie you can't get an extra spin tomorrow if you miss today's one) and it's supply must be lesser than the user's maximal demand (eg limiting boss kills to 99 mobs per day is pointless if the best user takes two hours to kill one anyway).

However, it's badly implemented on this site because users get the carrot regardless of participation. For example, my old posts can continue to hit daily rep limit regardless of any present participation.

Answer 10

1. I think preventing addiction is not the answer - the rules are determined by the company, and the company has no reason to prevent us from becoming addict.

2. I think, “gaming the system” is not an answer - writing well-received posts is everything but not gaming. This idea is very contraproductive and suppressive.

3. I think, “leveling the playground” is not an answer - getting the rep for your posts is not something what should be leveled, but your well deserved reward for creating valuable content.

What can be the answer:

4. Rep represents the usefulness of the posts of the user. This roughly relates to the upvotes what he has got, but not entirely. You can check the highest voted SO posts - yes a post with 8000 is typically useful, but not 8000 times more. The ratio of the real usefulness and the post score is not entirely linear. The well… “simplest” option is to handle these is capping them, and the SE system has a habit of using always the possible… well, “simplest” rules. (Well, maybe capping the post scores at +10 would be yet more “simple”¹.)
5. Posts with extreme scores tend to cause troubles in generating stats. Compare someone with 1 answer with +8000 and 800 answers with 0 - this is luck. Another user writing 800 answers with +10 - this is an unthinkably useful answerer. This might be a try to decrease the count of such “spikes” (or, at least, to decrease their effect to the rep).
6. Some leveling might be still a reason - Jon’s first place on the SO will probably remain in the next 3-5 years, despite that his activity hugely decreased in the last years. But the second, third and fourth most high-rep SO users seem to have a quite strong race. The relation of their rep depends mostly on the accepted answers and the bounties won (these are not repcap-affected). Without a rep cap, there would be no race, because the third and fourth users had no reachable way to get over the second.

¹_{If a company employee reads this: please dooon’t!}