I'm 27 years old and I'm applying to university. On the applications it ask the student to list activities and employment during time away from school. I played online poker for living for ≈4 years, should I mention this? Or would I be looked down upon and perceived as a gambling addict? There's no room on the application to go into details.
If I don't mention it then I'll have this big empty gap with no jobs listed – only activities. I'm applying for undergraduate studies into CS.
I like @DanRomik's analysis, but the same analysis leads me to a different conclusion: yes, list it.
First, it gives a better picture of who you are and what you have been doing.
Second, while some people may be prejudiced against poker players, in most applications there are things (and lack of things) that may be viewed positively by some committee members and negatively by other committee members. I don't think the concern should be too great that it will lead to too much veto-ing of your application, as might be the case for being incarcerated for a violent crime, say. (Of course this is my personal opinion and not based on any hard data from surveys--I imagine it might be an issue at some schools, but probably not most.) I personally would find lack of activity for 4 years more of a concern.
Third, the fact that you are no longer playing poker professionally (I infer this from your use of past tense) indicates that, even if you were addicted to gambling at some point, you overcame it.
Lean yes, provided it was legal. Professional poker takes a tremendous level of mathematical acumen and discipline. Given that this is a tremendous qualification and, you know, explains what you've actually been doing, you definitely include it. My guess is computer science professors understand the weight this carries, but you should use your essay to flesh out how it's challenging.
All else being equal I would not assume the committee is tremendously moralistic and I certainly wouldn't carve an application around the biases they might hypothetically have.
I think it's worth addressing your question on two levels, the practical level and the philosophical/ethical level (which by itself also has some bearing on the practical level).
On the practical level, it sounds like both the options of mentioning or not mentioning your poker occupation carry some risk. It cannot be denied that some people may perceive your choice of making a living from a card game as a negative, or at least not a positive, thing, whether this is justified or not. On the other hand, an unexplained 4-year gap on your CV would also very likely be perceived as a negative thing, perhaps by an even larger number of people than in the case of poker.
More positively however, if you were successful enough as a poker player to be able to make a living out of it for several years, that can say several good things about you that may impress even some people who tend to disapprove of poker. For example, if you want my personal opinion, I would infer that you are intelligent and have strong analytical skills, while at the same time not exactly getting the impression that you have strong altruistic tendencies or are especially passionate about using your talents for the good of society; of course, if I found out that you also volunteered at a homeless shelter or donated half of your poker proceeds to charity, my impressions on such things can change. If you are considering mentioning the poker, it may be a good idea to mention specific achievements in this area (e.g., which/how many tournaments you won).
Now, to address the more philosophical aspect of the question, I think as a matter of principle there's something to be said for being honest about what you have been doing with your life (as long as it's a legal activity), even though it may be a somewhat controversial activity that risks bothering or offending some people. More to the point, as I said this philosophical argument maps to the practical level, in the sense that if I were reading your application I would be somewhat impressed by the fact that you chose to mention it despite the obvious risks, independently of anything else, and would see that as evidence of a certain amount of character (at least if you didn't mention it in a way that seemed very cavalier or arrogant). Now, whether that positive impression would be enough to counterbalance the negative impression I would get if I were the sort of person who strongly disapproves of card games, is hard to say; probably for some such people the answer is no. For my case specifically, while I have a mild disapproval of someone with obvious talents taking up a form of employment that has essentially zero societal impact (whether it's poker or many other less controversial types of employment with the same characteristic), I do think the positive effect of seeing you take ownership of your lifestyle decisions in an honest way could actually make me see you in overall a quite positive light.
So should you mention it or not? I don't know. Only you can decide that, and given how critical of a decision this is, it would be irresponsible of me to give you any definite advice, even if I had a strong feeling about what the correct choice is, which I don't. I hope this analysis can still be a bit helpful though. In any case, good luck.
There have already been some great and thorough analyses. Adding to Dan Romik's and Kimball's assessments, I would focus more on the latter's philosophical argument, which may also play into the practical. Agreed, there will always be some risk in mentioning the poker playing, but not mentioning it could be considered tantamount to misrepresentation. If you leave it off and it is later discovered (sometimes the likelihood of something coming out in an unexpected way is directly proportional to how much one didn't want it discovered) that could be grounds for revoking any admission offer, presuming that you had to beat out other candidates who we (or the university) assume did not misrepresent themselves on their applications.
As an aside, a hole in your CV is not automatically the worst thing ever. It is not the best, but I would suggest it also depends on what came before. If one were gainfully employed for years before a gap, economic climate in a country/job area, medical reasons, etc may also be considerations. Having said that, personally, I would still go by the first paragraph and declare it, although as others have noted, only you can make the decision of a course with which you are most comfortable.
I faced the same problems with employers. I have a decent poker CV, could say I was ranked #1 globally for a particular game and format over an extended period (years)
Almost everybody (including my parents) hated it but some others were extremely receptive towards it. In analytical professions and studies poker is complimentary and some people in those professions will recognise this. In other professions poker is looked upon extremely negatively
The odds of a middle-aged university staff member being impressed by poker are low. It suggests a rebellious streak and wasted talent - anybody who can beat poker for a living could and should do any number of other things
People don't really read all of applications/CVs. They scan for a few facts, in your case it will be your previous academic record and work experience. It's definitely better to add poker than have a blank but I would include either achievements or estimated earnings beside this
The one thing you can't do is let anybody believe you were a degenerate sitting with your laptop, drinking beer, smoking weed, playing poker and calling it work. We all know you wouldn't do that now, right? :-)
I'll suggest one of two options.
It's one thing to write "I played poker online a lot and lived of my winnings." It's another thing entirely to say "I developed a statistical algorithm for multi-round poker tournaments while affiliated with ACME online games inc." the more you can make it professional-sounding (not necessarily with the angle I've demonstrated), the better it sounds.
I'm sure you didn't play from dawn to dusk, get drunk and go to bed for 4 years, right? You're applying to be an undergrad, not a R&D team leader. Maybe you spent time doing volunteer activities? Helping your family out? Pursuing an interesting hobby? Traveling abroad? Even if that doesn't cover all that much, you can play it up.
PS - If your grades are good, I don't think anyone would care what you did before your undergraduate studies. I mean, maybe for a scholarship, but not beyond that.
