Guest Author: Michalina Malysz

“Like you use sentences to tell a person a story; you use algorithms to tell a story to a computer” (Rudder 2013).

In today’s day and age, we have the world at our fingertips. The internet has made many things easier, including dating, allowing us to interact and connect with a plethora of new people–even those that were deemed unreachable just fifteen minutes beforehand.

Inside OKCupid: The math behind online datingtalks about the math formula that is used to match people with others on the website OKCupid, the number one website behind online dating. Christian Rudder, one of the founders of OKCupid, examines how an algorithm can be used to link two people and to examine their compatibility based on a series of questions. As they answer more questions with similar answers, their compatibility increases.

Using Fakes To Test Reactive Flows. Unlike mocks, fake implementations give us full control of our dependencies in unit tests, allowing us to accurately and thoroughly test. OkCupid Tech Team. Cutting Through the Static — Find and Fix Issues the Smart Way with Android Studio Static Code. The observations and statistics were catalogued in the blog OkTrends, written by OKC co-founder Christian Rudder, which started accumulating some 1 million unique views per post.

You may be asking yourself how we explain the components of human attraction in a way that a computer can understand it. Well, the number one component is research data. OKCupid collects data by asking users to answer questions: these questions can range from minuscule subjects like taste in movies or songs to major topics like religion or how many kids the other person desires.

Many would think these questions were based on matching people by their likes; it does often happen that people answer questions with opposite responses. When two people disagree on a question asked, the next smartest move would be to collect data that would compare answers against the answers of the ideal partner and to add even more dimension to this data (such as including a level of importance). For example- What role do the certain question(s) play in the subject’s life? What level of relevancy are they? In order to calculate compatibility, the computer must find a way to compare the answer to each question, the ideal partner’s answer to each question and the level of importance of the question against that of someone else’s answers. The way that this is done is by using a weighted scale for each level of importance as seen below:

Level of Importance Point Value
Irrelevant 0
A Little Important 1
Somewhat Important 10
Very Important 50
Mandatory 250

You may be asking yourself ‘How is this computed?: Let’s say you are person A and the person the computer is trying to match you with is person B. The overall question would be: How much did person B’s answers satisfy you? The answer is set up as a fraction. The denominator is the total number of points that you allocated for the importance of what you would like. The numerator is the total number of points that person B’s answers received. Points are given depending on the other person’s response to what you were looking for. The number of points is based on what level of importance you designated to that question.

This is done for each question; the fractions are then added up and turned into percentages. The final percentage is called your percent satisfactory – how happy you would be with person B based on how you answered the questions. Step two is done similarly, except, the question to answer is how much did your answers satisfy person B. So after doing the computation we are a left with a percent satisfactory of person B.

The overall algorithm that OKCupid uses is to take the n-root of the product of person A’s percent satisfaction and person B’s percent satisfaction. This is a mathematical way of expressing how happy you would be with each other based on how you answered the questions for the computer. Why use this complex algorithm of multiplication and square-rooting when you can just take the average of the two scores? Well, a geometric mean, which is “a type of mean or average which indicates the central tendency or typical value of a set of numbers” (Rudder, 2013), is ideal for this situation because it is great for sets of values with wide ranges and is great at comparing values that represent very different properties, such as your taste in literature and your plans for the future and even whether or not you believe in God (best of all, the algorithm can still be useful even when there is a very small set of data). It uses margin of error, which is “a statistic expressing the amount of random sampling error in a surveys results” (Rudder, 2013), to give person A the most confidence in the match process. It always shows you the lowest match percentage possible because they want person A and person B to answer more questions to increase the confidence of the match. For example, if person A and B only had answered two of the same questions margin of error for that sample size will be 50%. This means that the highest possible match percentage is 50%. Below I have included a table that shows how many of the same questions (size of s) must be answered by 2 people in order to get a .001 margin of error or a 99.99% match.

Now that we know how the computer comes up with this algorithm, it makes you wonder how do these match percentages affect the odds of person A sending one or more messages to person B. It turns out that people at OKCupid had been interested in this question as well and had messed with some of the matches in the name of science. It turns out that the percent match actually does have an effect on the likelihood of a message being sent and the odds of a single message turning into a conversation. For example, if person A was told that they were only a 30% match with person B (and they were only a 30% match), then there’s a 14.2 % chance that a single message would be sent and about a 10% chance of a single message turning into a conversation of four or more messages. However if person A was told that they are 90% match (even if they are only a 30% match), then the odds of sending one message is 16.9% and the odds that the one message turns into exchanging 4 or more is 17% .

I believe that the future of online dating is very broad and exciting. However I have some concerns about the algorithm and that it relies heavily on a person’s honesty and self-assessment. If I was to further analyze this topic I would look into how the length of the first message affects the response rates. Also, how it affects the odds that the conversation will continue for four or more messages and whether those messages would the same length or longer/shorter than the initial message sent. The extent of the questions that have yet to be asked about this particular set of data and the idea of online dating/ matching with people who are possibly oceans away are enormous; however, the data will linger on the Internet for many years to come and I’m sure will analyzed hundreds of times more to answer many many more questions.

Citations:
Hill, K. (2014, July 28.). OKCupid Lied To Users About Their Compatibility As An Experiment. http://www.forbes.com/sites/kashmirhill/2014/07/28/okcupid-experiment-compatibility-deception/#4cbde4745eb1
Match Percentage. (n.d.). Retrieved April 26, 2016, from https://www.okcupid.com/help/match-percentages
Rudder, C. (2013, February 13). Inside OKCupid: The math of online dating. [Video file]. https://www.youtube.com/watch?v=m9PiPlRuy6E
Rudder, C. (2014). Dataclysm: Who We Are*. New York: Crown Publishers.
Figure 1. Margin of error vs. highest possible match. From “Match Percentage,” https://www.okcupid.com/help/match-percentages. Copyright[2015] by OkCupid. Reprinted with permission.
Figure 2. Odds of sending one and/or more messages from 30% match. From “OkCupid Lied To Users About Their Compatibility As An Experiment,” by Kashmir Hill, 2014, http://www.forbes.com/sites/kashmirhill/2014/07/28/okcupid-experiment-compatibility-deception/2/#2f78a64f5eb1. Copyright [2014] by Forbes. Reprinted with permission.
Figure 3. Odds of a single message turning into a conversation based on match percent. From “OkCupid Lied To Users About Their Compatibility As An Experiment,” by Kashmir Hill, 2014, http://www.forbes.com/sites/kashmirhill/2014/07/28/okcupid-experiment-compatibility-deception/2/#2f78a64f5eb1. Copyright [2014] by Forbes. Reprinted with permission.

Women over the age of 20: OkCupid finally has pulled together a study that explains why men now find you physically repulsive. Handy! The study, found in OkCupid co-founder Christian Rudder’s new book Dataclysm: Who We Are (When We Think No One’s Looking), purports to show that while women on the site remain primarily attracted to men their own age well through their 40s, men stay attracted to 20-year-old women for, well, pretty much their entire lives. As Rudder himself puts it: 'From the time you're 22, you'll be less hot than a 20-year-old, based on this data. So that's just a thing.'

Dataclysm: Love, Sex, Race, Identity - What Our Online Lives Tell Us About Our Offline Selves, $10, Amazon

'A thing,' indeed. The chart documenting the study has already been spun into a number of alarmist and alarming trend stories (like this great Daily Mail headline: “Are you a girl over 22? Then don't even bother with online dating”), and fits in nicely with the rising trend of articles and studies declaring various ages as the time when women become most beautiful and/or stop being hot forever. Do women peak physically at 30, as this Allure-sponsored study suggested? Are women suddenly hotter than ever at 42, as this memorably dunderheaded Esquire essay declared in July? Is beauty more important than age for women when it comes to landing a man, as this other recent study implies?

Okcupid Blog Post

Since most of us are raised from a very young age to both obsessively track our own worth by comparing ourselves to other women, and to obsessively track the relative peaks and valleys of our own romantic prospects, studies like this basically immediately nest in our brains, alien-from-Alien style.

But before you resign yourself to a future comprised exclusively of dating scarecrows that you have cobbled together from cat hair and water-logged copies of Modern Bride, there are some other facts to consider.

While these kinds of studies are always phrased ambiguously for maximum impact/ panic clicks, they're actually usually less closely linked to real-world behavior than they seem at first glance. In fact, Rudder himself noted that while these numbers reflect the “who’s liking who” information on OkCupid, the actual messaging patterns of men on the site show that they’re much more likely to message someone closer to their own age. And no lesser authority than the New York Times has picked apart the way Rudder draws secondary conclusions from the data he gathers.

But more importantly: these surveys chart the desires of EVERY kind of guy on OkCupid, not just the guys you'd want to date. The study takes into account the tastes of sexually overconfident Juggalos, guys who believe that “girls only like douchebags,” guys who think “I have already married and divorced you in my mind” is a good pick up line, and other men you would most likely not touch with a 10-foot 20-year-old. The reality is, none of us are trying to appeal to every heterosexual guy on OkCupid — or every heterosexual guy in the actual world, for that matter. So falling outside the lines of what a cross-section of every kind of straight dude in America finds desirable is not really much of a tragedy, and isn’t going to have a real impact on your dating life.

And perhaps most importantly: one of the things that changes most about dating as you age is the qualities you desire. Though many of us consider hotness a primary priority when dating in our late teens, when we get older, that generally begins to come second to the kind of qualities that make a man someone you're able to spend the next 20-60 years around without constantly wanting to fake your own death. And —shockingly!— men who want to partner up also want to find someone who's actually pleasant to be around and build a life with, instead of just finding whatever cute young dummy is most easily available. And you know what else? Dudes who do want that cute young dummy? YOU DO NOT WANT TO DATE THEM ANYWAY! There’s a lot more at work in successful love and romance besides the “lust” that Rudder refers to here.

Okcupid Blog Height

So please remember to take all of these kinds of studies with a grain of salt. While there's a lot we can learn about human behavior from what people do when 'no one is looking,' there's a lot you can learn from the way people act when we're looking, too.