Geek Logik Answers All Your Relationship Questions
    By Garth Sundem | April 25th 2008 06:47 AM | 17 comments | Print | E-mail | Track Comments
    About Garth

    Garth Sundem is a Science, Math and general Geek Culture writer, TED speaker, and author of books including Brain Trust: 93 Top Scientists Dish the...

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    It's been just over three years since I got married, and I remember thinking (amid the nearly debilitating fear that we would run out of alcohol at our mountain cabin wedding and thus trap our families in a scene from The Shining) that it would be wonderful to finally be free forever from the intrigue and confusion of dating.

    You can't fault the optimism.

    Now, through the lens of hindsight, I realize that I should have known that dating and even cohabitating were only warm-ups for the big dance.

    Example: I didn't really mind the eggshell color of our living room walls——it provided a functional backdrop to both the climbing/skiing pictures taken by a friend in Patagonia, and to the portraits of Italian cafes and riverboats Kristi's father painted, which we hang in place of the climbing photos whenever he visits.

    However, to Kristi, the color was "dead guy white." Let me also explain that we have rather complex crown moulding framing the stuccoed ceiling, making painting nearly akin in needed time and expertise to completing a PhD in particle physics. She wanted something "bright and cheerful, like a nice sunshine-pumpkin. Oh and blue trim."

    I really had no idea what I wanted other than not to paint the living room sunshine-pumpkin with blue trim. Needless to say:

    And I should have known from the start. Why, I wonder, didn't I realize sooner the way the wind was blowing and just paint the darn thing, rather than creating relationship strife to the tune of then also needing to put a skylight in the upstairs bedroom?

    I needed an equation—something along the lines of "Is she really serious about that home improvement project?"

    I thought, though, that before getting to this one, I would look at some more fundamental equations that govern marriage.

    In the equations below, the first is based on solid statistics — an 11,000-person study by the CDC that explored factors that help and hurt a marriage's chances of working (for example, they found that if a woman is married before age 24, her chances of staying married for 15 years decreased by 30%).

    These statistics were easy to write in math terms, and the equation does fairly accurately predict your chances of being married at time "T".

    Granted there are other factors that might help or hurt your specific marriage, but the CDC study found that, for most people, these are the biggest factors. Remember that the average for all marriages is only about 50% and if you get a low number, please accept my very best wishes in bucking the odds.

    The other two ("Should we get married?" and "How many kids should we have?") are a bit more shoot-from-the-hip. With this kind of equation, I try to make the math match common sense. If you put in honest numbers, they return honest answers, but they're not quite as scientific as the first.

    So, good luck, have fun, and check out posts deeper in the blog for additional marriage-relevant equations.

    What are the chances my marriage will last?

    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. stands for “Happily Ever After” and is the percent chance you will still be married at time “T”

    Should we get married??

    T= How many years have you been dating?
    L= The number of times per day that something makes you think of this person
    C= If your families got together for a holiday dinner, the estimated number of times there would be uncomfortable friction
    S= How many shared interests and/or goals do you two have?
    A= How many individual or conflicting interests and/or goals do you two have?
    D= The average number of disagreements you have with this person in a month

    If Ttk is above one, you should tie the knot.

    How many kids should you have?

    S= Your combined household salary
    K= Combined, how many brothers and sisters do you and your spouse have (include yourselves in this number)
    T= Combined hours per week you and your significant other work outside the house
    A= On a scale from 1-10, the highest level of aversion you have to any of the following: Changing diapers, sleep deprivation, visiting in-laws, tantrums
    E= On a scale from 1-10, how concerned are you about global overpopulation

    Kids, of course, is the number of kids that your lifestyle supports.

    Here is my appearance on Good Morning America talking about how to use these relationship equations:


    interesting content thx for sharing... the logic is my best section in math.

    interesting content thx for sharing...


    thank for article

    great post
    thank for information

    great post
    thank for information

    yes great, thanks


    I used your widget to compare our marriage to another couple we know. He was 28 at marriage, they have 3 kids, 24 years combined post high school ed (both are md's), 5 for religion, 1 parental divorce, no prev. marriages for either, 21 years together. They got a 94% chance of their marriage succeeding.

    My hubby's age at time of marriage was 33, Our current combined years of post-high-school education is 10, no kids, religion is about 5, i Parental divorce, no previous marriages, 15 years together. We got a 64% chance.

    They are divorcing, we are happy as clams. Here's a variable you didn't allow for—midlife crisis—Mike sowed all his wild oats before marrying; we were together 4 years prior to marriage. Eric had just celebrated his 20th anniversary in April, and later that year started an affair with a married coworker (another dr who had his 3 daughters as patients, lied to his wife about it, got caught, wouldn't file for divorce but still carrying on the affair and living at home, wife got tired of him dragging his feet so she filed and kicked him out the same day. His response, "But I don't have anywhere to go." Pathetic! And his mistress is supposedly divorcing her dr/lawyer husband, but not until he starts making good money so she won't have to pay off his student loans, which is going to be quite a while since he is not practicing medicine or law, but selling built to spec medical buildings on commission. Oh yeah, he has an office in the same building (small-only 3 floors) as the other two. And Eric's daughters (21, 19, & 16) are devastated, his wife is heartbroken that he chose his mistress over her (he never even tried to save his marriage; she asked him to stay and work on it with her) and his youngest is not speaking to him until he gets rid of that woman. You don't need algebra for this—just use the nearest donut theory—men are lazy; even if they have a good meal waiting across town, they'll usually just reach for the nearest donut.

    So much for the algebra theory!!


    This is a rare formula for Indian couples (But those days are gone)

    Now I know what I want in a dating relationship. My dates are more productive and fun.I am no longer wasting time.

    For me the formula was 2 for "I should tie the knot". Still, if this doesn't work I can always get a marriage retreat and apply the formula on another person OR I can ignore these things as love has nothing to do with math!
    Is there a variable for increasing chance of divorce for each successive remarriage?

    i.e. - If a woman first gets married at 18, second marriage at 24, third at 30, fourth at 33, fifth at 39?

    Her age at marriage goes up, but the number of previous marriages goes up as well. It seems you could have a formula based on the previous marriage?

    Did the CDC really say that those who've already been married 30 years are only 1/3 as likely to have a lasting marriage as are those who've been married 1 year? That's what the final term says, unless I'm making some extremely dumb error. (100/(102+2P)) will always be less than 1, so taking it to the power 2T makes it smaller as T (years at which you are computing the chances) gets bigger. So at year 1 the value of (100/(102+2))^2T is just a lttle under 1, while at year 30 the value is around 0.3???

    Unless I misunderstood the meaning of T? I just realized that maybe you didn't mean T to represent "how many years has the couple already been married" but rather something along the lines of "at what distance in the future do you want to calculate their odds for still being married?" Seems unlikely that you meant that, given that the whole article claims to measure the odds of "happy ever after" and that would presumably be defined as the odds of *never* getting a divorce, rather than the odds of "not getting a divorce in the next T years". Still, the alternative, that I read it right and people who have been married a long time have a *higher* chance of getting divorced, seems even more unlikely.

    Is it too late to ask for a clarification?

    Hehe! Love it! Funny and entertaining. Though I don't believe in the equations above, hehehe. Goodluck for those who will use this!

    I think you forgot a few key weighted qualitative variables such as self discipline, spirituality, physical fitness, health (mental and physical), sexual prowess, attractiveness, independance, and family values.