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Are they really right for you? Don’t leave it to your heart to decide… let the math do the judging! Here are three mathematical theories to help determine if your marriage will last (or if it should happen at all).
1. The Mathematics of Marriage
In their book, The Mathematics of Marriage, mathematician James D. Murray and psychologist John Gottman describe their use of calculus to study interactions between couples. Using a model Gottman developed in 1979, the pair surveyed 700 newly married couples in King County, Washington in 1992. They analyzed couples’ 15 minute conversations using a scoring system that assigned a number based on each statement, expression, and even pulse rates. Then they model quantified the ratio of positive to negative interactions during the talk. The magic ratio was 5:1. When the ratio falls below this, a relationship may be in trouble.
These numbers were plotted as a function of time and were used to make predictions as to whether the couple would i) divorce, or ii) stay married a) happily, or b) unhappily. They called this the “Dow Jones for Marital Conversation.” Every 1-2 years until 2004 the couples were asked to complete a questionnaire assessing their marriage. The predictions on which couples would get divorced was 94% accurate, and typically divorce occurred after 4 years.
2. The 37% Rule
In 1997, Dr. Peter Todd of the Max Planck Institute in Munich described his 37% rule, also known as the secretary rule. Imagine if you have to fill 1 secretarial position and have n # of applicants, ranked from best to worst. Now, here’s where the math gets hairy. Assuming you skip the worst ones (n/e of the applicants where e is the base of the natural logarithm), and you only interview applicants who are better than those you have already interviewed (n/e + 1 is better than all previous n/e interviews), the probability of selecting the best applicant from the pool rounds to 1/e, or around 37%. Hence, you should be able to pick the best secretary after interviewing 37% of the applicants.
If there are about 100 potential “mates” you don’t have to date 37 people to finally meet Mr. Right, #37. Instead, Dr. Todd advises you set your “aspiration level,” what you are looking for in a partner, to a range. Then date only those who are in the top 25% of that range. Your sample size, therefore, is reduced to only 10 dates. One of those should make the cut.
3. The “What are the Chances My Marriage Will Last?” Equation
Garth Sundem, author of GeekLogic created his own equations to determine: 1. What are the Chances My Marriage Will Last? 2. Should We Get Married? and 3. How Many Kids Should we Have?The “What are the Chances my Marriage Will Last?” is based on an 11,000 person study by the CDC that explored factors that help and hurt a marriage’s chances of working. Here’s the equation:
where A= Her age at time of marriage
E=Current combined years of post-high-school education
K= Number of kids from this marriage
R= How religious is the couple (1-10 with 10 being “the Pope”)
D= Combined number of divorces of couple’s parents
P= Combined previous marriages
T= Years at which you are computing the chances
H.E.A. = % chance of Happily Ever After
But don’t worry about calculating it out yourself. Over at Political Calculations, you can type in your personal data and it spits out the probability you and your partner will still be married at a given year of anniversary.
Comments (12)
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They forgot the most obvious… I met my man in a college discrete structures course!
posted by Sondra on 7-29-2008 at 9:49 am
Here’s the problem with the 37% rule: it looks at a spouse as a role that needs to be filled. I believe many divorces are a result of this idea that everyone NEEDS to get married. I look at marriage as something I may consider IF I find the right person, not as a job I need to fill with a qualified applicant.
posted by Craig on 7-29-2008 at 10:43 am
Craig, you spelled out my thoughts about marriage exactly.
@the post, the math became too complicated for me to follow!
my recptcha:
companion guion (whatever that means)
posted by septer on 7-29-2008 at 11:02 am
My fourth anniversary is in December. My wife and I have a 122.38% chance of remaining married until then. But, we only have a 29% chance of staying married until our 40th anniversary. I guess my wife is right, we need more kids.
posted by Witty Nickname on 7-29-2008 at 11:28 am
I completely agree with you as well, Craig. It seems such a huge majority of people is so obsessed with not being *alone* that they settle. After that, it’s only a matter of time before they realize how unhappy they are.
recaptcha: consists con
how appropriate…
posted by Orange on 7-29-2008 at 12:47 pm
My husband and i apparently have a 23% chance of making it to our 50th.. maybe another kid will help improve those odds.. at what point does the number of children start increasing the chance of divorce through additional monetary and emotional strain?
posted by Bekka on 7-29-2008 at 1:23 pm
My husband and I had a 40% chance of making it to our 4 year anniversary, which was last April. Here’s to beating the odds! Since I’m at my happiest I’ve ever been right now I’ll just see the 40% as a good thing.
posted by Tricia on 7-29-2008 at 1:56 pm
I got all depressed when the calculator on PoliticalCalculations gave my boyfriend and me only a 9% chance of making it to our 25th anniversary (provided we marry in the next two years and have a kid). But then I crunched the numbers for him and his ex-wife and it gave them a 102% chance of making it to the 5th year. They didn’t even make it to the second. I feel better now. :-)
ReCAPTCHA of appropriateness! dissent evidence
posted by mandapanda on 7-29-2008 at 2:57 pm
Well, my boyfriend and I have a 92.86% chance of making it to our 5th anniversary but only a 34.69% chance of 40th
posted by Karen on 7-29-2008 at 4:35 pm
Boy howdy, I wouldn’t mind doing the math is there were anywhere near 100 potential mates available.
posted by Miss Cellania on 7-29-2008 at 4:39 pm
I just calculated it for my ex boyfriend. If him and I were to get married this year, we would have a 23.23 chance of making it to our 5th anniversary. Glad we cut it off.
Apparently my parents were lucky. They made it till their 22nd anniversary before they divorced, but the calculations say that they had a 25.27% chance of making it till their 20th anniversary. Considering the amount of postsecondary education they had (14 years combined), those are low odds.
Maybe I should go ahead and date my crush. If we waited seven years (my magical number of how long to date until marriage is a topic), those odds jump to 47% with us staying till our 5th. Though I should probably up the religious factor in this, considering he’s very religious while I’m not (but he’s Jewish, which I find fascinating, and he loves talking about it with me). Or maybe I’m just unlucky and should just stick to small flings.
posted by Nicole on 7-29-2008 at 4:52 pm
A slight quibble. There is NO evidence that being religious decreases your chance of divorce. In fact it increases the chances. Google “divorce rates by religion” since since mental floss won’t let me point a link to my source.
I am college student who is watching their friends starting to get married. The first to get married are the most religious. They usually do it out of desire for sex or being forced into it by parents. What’s my point?
ZOMG Atheist marriages FTW. Garth Sundem made of fail. I hate it when religious people lord this stuff over the non-religious despite the fact that they are wrong about everything.
posted by Nathan on 7-29-2008 at 7:56 pm