What’s Wrong With the OkCupid Algorithm for Matching People?


My blog assistant sent me this link about the science behind OkCupid’s algorithm.

I watched the seven minute video and while I found it entertaining, I saw two big flaws in the way OkCupid purports to match you based on compatibility:

1) OkCupid has three pillars of their algorithm – what you think, what you want your partner to think, and how important it is to you.

This all makes sense in theory, but it falls apart in practice for this reason: people don’t know what’s good for them. Really. If they did, I would be out of a job.

Simply put: what you’re attracted to and who you’re compatible with are two very different people. Most people – myself included – are wildly attracted to the opposite sex versions of themselves. Do you like skiing? Then HE better like skiing!? You’re charismatic? HE better be charismatic! You make a lot of money? HE better make a lot of money! Such commonalities may cause you to be more attracted to someone, but none of these things are good predictors of true compatibility.

That second pillar of the OkCupid algorithm doesn’t say much of anything – it only goes to show how narcissistic you are in searching for someone who is just like you.

As such, that second pillar of the OkCupid algorithm doesn’t say much of anything – it only goes to show how narcissistic you are in searching for someone who is just like you. For this algorithm to work, people would have to be a LOT more self-aware about compatibility – and they’re not.

Because you could find a neat-freak who likes being the center of attention, but if he doesn’t believe in marriage, or doesn’t make a livable wage, or doesn’t believe in sharing household duties, it doesn’t matter.

2) The way OkCupid weights importance is seriously out of whack (see 4:43 in the video).

Irrelevant = 0
A little important = 1
Somewhat important = 10
Very important = 50
Mandatory = 250

A little important is BARELY scored higher than irrelevant. Mandatory is TWENTY FIVE times more important than “somewhat important”. I’m positive some very bright people put some thought into this and decided on this scale, however I don’t know how “somewhat important” can be ten times more valuable than “a little important”, while “very important” is only five times more valuable than “somewhat important”. It’s all very arbitrary and inconsistent, if you ask me.

Frankly, I think eHarmony’s compatibility testing is probably smarter and more relationship-based than OkCupid. The problem, of course, is that eHarmony took all the fun out of their questions and removed attraction from the equation. So you have OkCupid, which is fluffy compatibility pseudoscience based on physical attraction and common interests (as if mutual love of horror films has anything to do with anything) and eHarmony, which is undoubtedly deeper, but ignores the base human impulse to look up attractive faces. Most people I know are using OkCupid because it’s more fun, not because it produces better matches.

Your thoughts, below, are appreciated.

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  1. 1
    Karmic Equation

    Well, I guess I’m an opportunist when it comes to OKC’s matching.

    Sometimes when I reply to msgs with Dear John notes, if they’re clearly incompatible as in “Y’all got issues” in the tab, I just reply to the person that we’re not compatible.

    I’ve noticed some men will do the opposite. Particularly those with NO pictures or are “available” will start their message with “Wow, we’re 90% compatible” or some such. And When I reply with my Dear John, “You’re not what I”m looking for”, they’ll say “90% compatible is hard to find, maybe you should reconsider.”

    Frankly I personally don’t put much stock into the compatibility part but rather the “explanation” part. That clues you in to how the other person thinks and also gives you some clue as to their level of seriousness or humor.

    When I first joined OKC, I was curious and asked one of my online admirers what they looked at for potential dates. He says “First I look at “what she’s looking for” section. Then I look at her answers to the sex questions. Then I look at her “personality” tab.”

    He’s one of those guys looking just for hookups and not relationships, but he was very honest. Some of the other guys also mentioned they look at the explanations. My answers vary from serious to incredulous, and most are tinged with humor.

    I have since CLEARED all my questions and “skipped” all the sex questions except the ones where I was interested in the guy’s answers. The first time around, I was answering ALL of them, and, unsurprisingly, my personality labeled me as “More Sex-driven”. True, but not really something I need to have advertised on a dating site, hence the erasing of all the questions and starting from scratch 🙂

    Now My personality tab now has none of the “less…” and only has “more…” — Capitalistic, Experienced in Love, Spiritual, Kinky (on purpose I answered yes to a question and added a funny explanation), Mathematical, Spontaneous, Scientific.

    So picking and choosing what you answer is better than just sequentially answering questions that pop up. I usually go to an interesting guy’s “The Two of Us” and answer some of the questions he’s answered.

  2. 2

    I am both on eharmony and on ok cupid. I get more dates on ok cupid whereas my last date on eharmony was 4 months ago. The men seem all gung ho in the beginning on eharmony and do the whole eharmony communication but then it fizzles out. I do have one friend that met her husband on eharmony so it does work.
    I tend to make mandatory on ok cupid, the important things. Like I make it mandatory to not do drugs but there are some men who answer the question that they do do drugs so obviously that makes us uncompatible and I don’t waste my time.
    Other mandatory questions are:  1. do you like to cuddle? I answered yes because I think it’s important
    2. do you think drug use with your partner can be a romantic activity? I answered no because I don’t do drugs nor want a partner who does drugs. There are some men that have answered yes to this and that’s not the man for me
    3. do you have rape fantasies? I answered no and think no man should have this as a yes. It’s too f**ked up a fantasy to have
    4.are you looking for a partner to have children with? the acceptable answers are yes. there is no maybe so this question I don’t like as some men don’t know. at least on eharmony, men can answer maybe and maybe is an okay answer but at some point, the man will have to know whether he wants them or not.
    5. are you happy with your life? Yes is the answer I look for but again this can be lied about or partially true since it’s either yes or no.
    6. are you willing to have an open relationship. answer is no because I want monogamy
    7. do you believe contraception is morally wrong? only yes or no but I will only accept no because contraception is not a moral issue so I am weeding out someone who is overly religious.
    My only problem with ok cupid is that I think these questions are too black and white. There are too many yes/no questions where I would answer as maybe so it’s not open ended.

  3. 3

    Of the sites Ive tried, I actually like OK cupid the best. I like to see someones thinking in how they answer questions and in doing so I can pick up their type of humor or perspectives more than I can on other sites . Other things that make it fun are the quizzes you can take. Plus when other members grant you enough 4-5 star rankings you are rewarded with the “you are hot” status LOL . Then you know you’ve arrived !!!
    More seriously though, they might ask questions like are you still in love with an ex …and I pay attention to the answers. I also like to see the personality traits they formulate which are fun.   
    I heard OK Cupid is a site for more creative types. I found I got bombarded with high contact from guys 20-35 and Im 54.   Thats not my market !!

  4. 5

    I am on OKC and met a lot of great guys.The field is open, diverse, and it is free. I have the same profile on E-Harmony and Match.com that I paid for, and no one is talking to me. I am an African-American woman in her 30s and I feel like I am the most unattractive person in the world. OKC is more diverse than the paid sites. You will get odd people on all the sites.   And sometimes you want fun and something to start a conversation with. I met a guy on OKC and we dated for three years. I met guys on POF and dated for months.  
    Evan, I love but I must disagree with on this one. Especially if you an minority.  

  5. 6
    Karl S

    I’ve used a number of different dating sites over the years and I find Okcupid seems to attract a more intellectual and progressive demographic that appeals to me. I think the match system is a good starting point because you can also consider the “enemy” percentage of your partner. Most people I’m “low match/high enemy” with tend to have very different spiritual, political and sexual leanings to me which would no doubt cause clashing.

    So, while a 95% match may not *necessarily* be a better partner than 40% match in terms of their overall character, at least you won’t be arguing about each other’s worldview every 5 minutes.

    The Dating Persona Test is also the greatest thing quiz I’ve ever seen. I love making my friends take it as I try to guess their results.

  6. 7

    I think with everything you have to take it in stride. Just because someone is 95% compatible with you doesn’t mean they are your soulmate. I usually look at men who are least 60% compatible with me, its important that they share a similar worldview with me and that they believe in marriage, don’t want an open relationship and are looking for a partner to have children with. I also weigh things like “believes homosexuality is a sin” because I simply cannot be with someone intolerant.
    I have noticed to the men I score in the 80s and 90s with I tend to just get along with better so I think their system is pretty decent.
    As for eharmony, lame site. Used it for 3 months and met 4 men, not worth the money.

  7. 8
    Valery North

    @ EMK:
    While it seems to be a valid statement that most people don’t know what they are looking for (echoed by some of the other dating advisers whose blogs I follow), and that this is a weakness in the algorithm’s premise, it is not valid to say that, “it only goes to show how narcissistic you are in searching for someone who is just like you.”     People have the option of choosing what seems to be a good match.     As the video explained, “centre of attention” works better if they are not similar (usually).     There are also many many more questions, and users can pick which ones are relevant to them.
    (as if mutual love of horror films has anything to do with anything)
    According to OkCupid’s statistics research (sadly, I can’t find the post any more), similar answers on the horror movie question is one of the strongest predictors for a positive outcome of a match.     So, arguably, it has a lot to do with something.

    1. 8.1
      Evan Marc Katz

      Don’t believe everything you read, Valery. Here’s the blog post:

      To figure out if you have long-term potential, ask your date (and yourself!)…

      Do you like horror movies?
      Have you ever traveled around another country alone?
      Wouldn’t it be fun to chuck it all and go live on a sailboat?

      Of all questions appropriate to a first date, the three listed above were the ones couples most often agreed on.

      In fact, 32% of successful couples agreed on all of them–which is 3.7× the rate of simple coincidence.

      I know I’m a dating coach and not a statistician, but I’m still voting for coincidence. There may be a neat correlation, but it’s not causality. In fact, when you think about it, these questions could not be LESS relevant to the majority of the population. Most people don’t care about horror movies or had the money or freedom to travel alone or live on a boat. So does it make sense that 90% of the people said “No” to all three of these questions? Sure, it does. Does it make sense that the “adventurous” 10% said yes to all three questions? Yes. Does this have ANYTHING to do with what it takes to build a genuine 40-year-marriage – which is what compatibility is REALLY about?

      You’ve gotta be f-ing kidding me.

  8. 9

    I like OK Cupid’s matching system, but I’ve never used another site, so I don’t have a good basis of comparison.   When taken with a grain of salt and used strategically, it works quite well.   When  I first started, I met with some high matches…we were eerily alike.   It felt unnatural.   I began to look for lower matches, and answers to critical questions that I felt were important (very much like those mentioned by other posters)  and this seemed to work better.
    The site is diverse, but I seem to be attracting men with advance degrees who are somewhat intellectual.   One of the first men I met up with gave me a detailed explanation of the matching system (he was an economics professor) and I immediately  understood its inherent quirks.   If someone weights a lot of questions very highly, that can really throw the whole thing off.  The question bank and explanations  offer great opportunities for humor, expanding on answers that should not be black and white, and understanding what someone’s values might be.   I haven’t even gotten to try another site yet as it’s working for me.   I’ve had 350 emails in 3 months, and  hundreds of Quickmatches.   I was only going to use it to sort of get my feet wet with on-line dating but I am going to stay with it a while longer.  
    I’ve met some great people on it so far, and it’s  very entertaining.  

  9. 10
    The InBetweener

    I also weigh things like “believes homosexuality is a sin” because I simply cannot be with someone intolerant.
    You’ve just proved the point Evan was trying to make.
    Just because someone finds something sinful does not mean that person is intolerant.

  10. 11
    David T


    A correlation is still meaningful even if the underlying causality is not understood. Example: it took decades to figure out why living in Colorado Springs correlated with low levels of tooth decay. Studies eventually revealed it was the presence of naturally occurring fluouride in the water, but before that was understood, it was still true that if you grew up and lived in that town, you wouldn’t get many cavities.

    In the case of the Three Questions, maybe the   sailboat wishers are shirk responsibility or want to run away from difficult situations or topics.   In general, that ‘tude does not make for a good relationship partner, so maybe successful couples tend to have both partners saying “no” to that one. Maybe hating horror movies has to do with compassion. Maybe traveling alone could have to do with similar levels of curiosity and adventure seeking.   The “why’s” could be helpful in understanding compatibility, but not knowing them doesn’t make the correlation any less useful a predictor, as long as it is statistically sound.

    I remember that OKC blog, and what struck me about it and am surprised you didn’t mention, is that   68% of successful couples didn’t agree on those questions. While those three questions might be the most effective predictor of success the study found, it still isn’t very effective. They aren’t the whole story and there are plenty of viable partners with whom you won’t agree with on those three questions.

    1. 11.1

      Very well said. I saw this list back when it first came out and could see what the second two questions were really alluding to, but hadn’t figured out exactly how an interest in horror movies could point to something more significant. compassion, interesting idea.

  11. 12

    Hi Evan,
    I’ve been reading your material for about a year but have never commented before. I thought this post was interesting because I’m from Sydney, Australia, and here the main sites are RSVP, eharmony and OKC.
    I really agree with the statement above by Karl above – ‘I’ve used a number of different dating sites over the years and I find Okcupid seems to attract a more intellectual and progressive demographic that appeals to me.’
    In Sydney, RSVP (the local “Match”) is much more mainstream, and eharmony has a bit of a religious bent at times. Which is totally fine, just not what I’m after. So I guess OKC just suits a certain type.
    I think it’s great you talked about the weightings though – I didn’t actually know that and was surprised how it’s skewed.
    I’ve actually tried OKC twice, about 2 years ago, then cue long dating break (due to frustration), and then again recently. This time, I read Finding the one online first : ) So my profile is now more interesting, and the way I answered questions this time was more thoughtful. I only answered ‘mandatory’ to a couple of questions, absolute deal breakers, mainly moral questions. For the rest I used your general advice about what’s important, and really considered if it would be a problem if a partner thought x or y, or liked horror movies or not. And I agree totally that stuff like this is irrelevant in the longterm! But it does help build a general idea of someone to see the kind of things they like, and it makes it easier in the first interactions I think.
    And surprise surprise – this time things have been much better!
    So I think OKC’s system can be good, you just have to know how to use it. (And applying your advice to it seems to work pretty well). If you run out of ideas one day maybe you could write a blog post for each main site, about generally how to use their set-up productively? (Though I haven’t read every article on here, maybe you already have written these!)
    Cheers and thank you for your work! Not sure if you ever tour or anything, but you have a growing fan base in Sydney – every single friend I have is now reading your blog. In conversations about dating we give each other advice prefaced with “evan said”. you’re our guru   : )

  12. 13

    @The inbetweener
    You’ve just proved the point Evan was trying to make.
    Just because someone finds something sinful does not mean that person is intolerant.
    Uh, yes it does. Sorry if that messes with your sense of the world around you. People who use religion as an excuse to dislike people/take away their rights are intolerant, literally by definition. It is important to me that I am not with a man like that, especially because we simply wouldn’t get along. You don’t know me at all so you can’t really tell me what is best for me. I just upset you.

    1. 13.1

      Around here <5 % of the people would consider that a sin

    2. 13.2

      I think the inbetweener was just making the point that all this question does is tell you if someone believes the bible or not.   Thinking something is   a sin does NOT mean they dislike those people or want to take away their rights.   Some people, not all, are able to separate religion and politics.   And for that matter, many “religious nuts” can hate the sin but love the sinner.   Hopefully Christians are more loving and tolerant (despite recognizing something as a sin).   That being said, Christians do have a different world view, so I can still understand you wanting to weed them out if it doesn’t jive with your own.

  13. 14

    Despite the above-mentioned flaws in OKCupid’s matching algorithms, I still think they are way ahead of the likes of Match in helping you get some insight to the personality of the person behind the profile.
    I’ve read Match profiles that sounded promising, but when I’ve seen that same person’s profile on OKCupid and looked at the matching stats and their answers to questions, I have seen a totally different side of them (which showed why we definitely wouldn’t be a match despite the initial suitability based on their profile description).
    In general I find that people on OKCupoid are more open in what they say about themselves in their profiles, and less likely to pen the cookie-cutter profiles that seem to be the overwhelming norm on Match.
    I happened to find a guy on Match whose profile said he was separated, but he was alive & well on OKCupid as a poly-amorous married man, posting photo’s of himself & his wife, etc. etc.. Luckily I read his OKCupid profile before I was about to message him on Match! Dodged a bullet there 😉
    The OKCupid Journal function was another great feature for showing / reading more about some one. Sadly I believe it has been discontinued.
    Plus – and it’s a HUGE, HUGE, HUGE plus – every single member of OKCupid has the capability of writing and responding to messages. Unlike Match where (last I heard) barely 10% of the members are paying members with messaging capability (and you almost have no way of knowing who’s in that 10% when you look at profiles).
    For these reasons, I way prefer OKCupid over Match, even though Match may boast a much larger membership in total.
    Now EHarmony….. sigh…. in my experience Eharmony was pretty useless. Like Match, you have no idea whether the matches they offer you are paying members with capability to message you. I found that 95% of the people I said “Yes” to turned out to be non-paying members who didn’t find my “Yes” enough of a motivation to sign up as paying members. A superior matching algorithm doesn’t help much if 95% of the matches it spits out are not active paying members!
    Same story with Chemistry – most of their members were Match members whose Match profiles were automatically ported over to Chemistry, and they were not paying members of Chemistry. I must confess that became pretty dubious about Chemistry’s matching algorithm when many of the guys they matched me with were the same guys who had rejected me on Match.
    At the end of the day, whether you both like horror movies (or not) is not going to determine whether you will have a good marriage that will last for 40 years. Uncovering true compatibility takes time (months for sure) and many conversations, but you have to get your foot in the door to begin those conversation.
    Indication of some common interests and/or common approach to some of life’s facets is a good start – even if it’s just the creative trigger for a first e-mail that says more than just “Hi, I think you’re cute”.

    1. 14.1

      Eharmony matched me with someone who felt oral sex was unnecessary. Ugh. After 30 years of no orgasms with someone who felt that way, I am absolutely grateful for okcupid’s questions.

  14. 15

    I used to like OK Cupid, but their questions were so addicting that I needed to spend time elsewhere. Plus, their questions ranged from “do you like exercise” to “if you could, would you give yourself oral sex.” Really…..geez! I used to provide funny commentaries after the answers and boy, the emails rolled in…..
    Interestingly enough, many guys would send me emails noting we were 99.9% compatible and we must be meant for each other……Really…..? I hold very little faith in the Ok Cupid methods of matching. I have tried eHarmony as well…..same….and Match, don’t care for their matching system either.
    Bottom line, you have to read profiles and see photos (hopefully current and full body photos) and go from there. I will say I have had much better luck with Evan’s Online Dating program. 🙂   It’s all a process…..
    Oh, regarding Ok Cupid, I will look at the Enemy % and if it’s over 30% then I usually pass….not sure why….just a gut feeling I guess.

  15. 16

    The percentages for OkCupid works only if people answer a lot of questions and give them weighting (and are those questions ever addicting!). I’ve been on both OkCupid and eHarmony. On occasion, I’d come across guys who were also on both. It was interesting to me that the guys matched with me on eHarmony had high relationship percentages with me on OkCupid.
    It was comforting to know that their matching was somewhat close. I concluded that OkCupid was a less expensive version of eHarmony.   😉

  16. 17
    Valery North

    @ EMK:
    My comment about the correlation was, of course, meant to be taken as tongue-in-cheek.
    On the other hand, if I wanted to play Devil’s Advocate, here’s how I would argue:Liking horror movies could be taken as indicative of similar preference for (certain types of) emotional stimulation and life experiences (e.g. it might be indicative of a liking for adventure or thrill-seeking), and it might also be indicative of shared social values on things such as censorship, or permissiveness generally, and so on.     There may be serious issues that underlie the superficial surface meaning.     I would probably argue that there are many different sets of attitudes that could produce liking or not liking horror movies, and so it probably doesn’t give any strong indications of those characteristics.     On the other hand, if someone puts it as a “mandatory” question, then it’s fair to say that for that person, there is something strong underlying their reasons for it.     You might not think it’s an important question, and that the answer doesn’t mean anything about anything, but the person who would be absolutely horrified to find their partner doesn’t share their view would disagree, and it might be for any of the reasons suggested above, or for something completely different.     To them, it means a big deal.     Which is why the weighting system, whatever flaws it may have, is a good idea.

  17. 18
    The InBetweener

    Julia #14


    Uh, yes it does. Sorry if that messes with your sense of the world around you. People who use religion as an excuse to dislike people/take away their rights are intolerant, literally by definition. It is important to me that I am not with a man like that, especially because we simply wouldn’t get along. You don’t know me at all so you can’t really tell me what is best for me. I just upset you.
    Speaking of intolerance…
    Most (if not all) of what you wrote in a response to me was simply conjecture.   Uh, no you didn’t upset me.   I never wrote that I knew you or knew what was best for you.   I tolerate sins from human beings nearly every day.   By the tone of what you wrote, you may lead a sinful lifestyle and may feel guilty that you are unworthy of being respected and loved from someone who may seem “holier than thou”.  
    To echo what EMK wrote: …people don’t know what’s good for them.

    1. 18.1

      OK, can we stop with this bullshit false equivalency that speaking out against oppression and prejudice is somehow even remotely comparable to the oppression and prejudice itself?   

      Shutting down intolerance is not intolerant.   Take your weak argument elsewhere, please.   

  18. 19

    Am I the only guy that never filled out those questions? It seems like such a gimmick. Reminds me of all those endless questionnaires girlfriends in the past tried to get me to do from magazines. And I’m pretty sure there isn’t a guy out there that actually takes it seriously.   Which brings me to another point. Women probably enjoy those just like they did with those magazine questions. Men who bother probably answer the questions in a way to get the most dates.(Truth be damned!)
    I agree that it assumes people answer truthfully. But it also removes a bit of the mystery and fun out of getting to know someone. And what happens to opposites attract?
    If you want a better system of picking dates. Have someone that knows you and has your best interest filter out the losers. Sometimes we’re just blind and need a little help.

  19. 20

    It’s also important to add that OkCupid provides a % if you’ve answered 200 questions or 20 questions. Thus, judging and dismissing a person because of a low match score can be very misleading. I personally find the questions useful – I actually read what men have to say in the commentary or I go right for the “unacceptable answers”— but I understand, from experience, that it means very little.

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