Tuesday, December 27, 2022

The odds of Lennon Scott's birth

The Scott Family
  Math is hard and precise writing even harder; try to combine the two, and mistakes are to be expected.
     In that light, are they worth pointing out? Or is that nitpicking? I go by the broken windows theory: that if you ignore the small errors, then bigger errors start happening. Standards ought to be maintained.
     Being statistically-inclined, not to mention a fan of babies, my attention was drawn to a story on the CBS website, despite its unlyrical (but no doubt search-friendly) headline, "This couple who shares a birthday just welcomed their first baby – on their birthday" by Caitlin O'Kane, about Cassidy and Dylan Scott, an Alabama couple who were each both born on Dec. 18, and who recently welcomed a new baby, Lennon, on their joint birthday. All was happiness until this sentence:
     "For the couple to have their baby on their birthday is a one in 133,000 chance, according to Huntsville Hospital for Women and Children, which shared the family's story on Facebook. "
     No. It's not. Not close. The chance of Lennon being born on their birthday was 1 in 365.
     To see whether the error was the hospital's or CBS's, I checked the cited Facebook page. This is how Huntsville Hospital put it: "On Sunday, Dec. 18, a chance that's one in 133,000 occurred when their daughter Lennon was born."
     Their mistake, though the writer, O'Kane — who graduated from Fordham University in 2014, went on to get her masters there and then has worked in TV ever since — is no neophyte, so should have paused to think about the figure. Off-loading responsibility by quoting the source making the mistake doesn't cut it.
     It's easy to see how the 133,000 was reached — 365 x 365 (which equals 133,225, but 133,000 will do). Either way, that is not the odds of the Scotts having a baby on their shared birthday. Rather, it's the odds of any two people who marry first sharing a birthday and then having a baby on that birthday. The odds for the two-part sequence of events, not just for the second occurrence.
     Do I need to show my work?
     Okay. My birthday is June 10. When I asked my future wife out, the odds of her also being born on June 10 were 1 in 365 (ignoring the leap year). Let's for argument sake say she had shared my birthday. Once married, the odds of us having a baby on that birthday were also 1 in 365. The 133,000 to 1 odds were the chances of a couple both meeting, sharing a birthday and then having a baby on that birthday. 
     To provide a metaphor, it's as if today, Tuesday, I flip a coin and it comes up heads, and the Huntsville Hospital for Women and Children declares the chances of that happening to be 1 in 14. When that actually represents the chances of me flipping heads on a random day of the week and that day turning out to be a Tuesday. The chances of the flip itself are 1 in 2.
     See? No? Well, I tried.  As I said, math is hard, for many, which is why it needs to be contemplated by professional journalists before being passed along to the public. Apologies to O'Kane — it sucks to have your flubs flagged, never mind commented upon, even on the obscure hobby blog of some old crocodile in Chicago. I am reluctant to highlight a small mistake of a media colleague. I've made my share. But that stat was quoted in mainstream publications around the world and not one, as far as I can tell, paused to figure out whether it is correct. Letting such matters pass with a shrug is how we get to a world where facts don't matter at all, and we're sliding down the slippery slope in that direction fast enough already. 


  1. Barbara Maginnis Palmer.December 27, 2022 at 6:53 AM

    My head is spinning. I decided I do not care about anyone’s birthday. Is this why you were a bit late posting this morning?

    1. No, the column posts at midnight, automatically. I just didn't wake up at 4 a.m. and send the letter, but slept in until 6, which is unusual.

  2. I try to tell people this all the time. Two people who know each other will show up at the same bakery in Paris at the same time and be astonished. The chances of that particular meeting may seem remote, but the odds that a traveler will meet someone they know--or someone who grew up on the same street--or someone whose mother was in the same dorm in college, etc-- somewhere are pretty great. Even if the odds really were 133,000 to one, that would still mean 25,000 people in the US are similarly situated.

    1. I've mentioned this book before, "A Drunkard's Walk: How Randomness Rules Our Lives" by Leonard Mldodinow (co-authored a book with Stephen Hawking). It goes a long way in explaining how things occur more frequently than one might expect.
      I think the oversight by O'Kane was more a proofreading error than anything else. All the same, those sort of things can take on a life of their own which is usually not good.

  3. Given what I have been able to determine about how babies are made (Research! Research! Research!), I would say the chances of that baby being born on her parents' birthday are considerable better than 1 in 365. All you need is a calendar, the ability to count back nine months, and some strategically-timed boinking.

    As for some more-random odds, did you ever do that math classroom exercise of going up and down the rows of students to see how many had the same birthday? In a class of 25-30, there would invariably be one or two pairs sharing a birthday, to the amazement of all, after which the teacher gets busy on the chalkboard to explain probability.

    As for our own family data points: My paternal grandfather, mother and sister were all born on May 22. My sister's daughter and my father were both born on March 25. Those combined birthday parties are real time-savers.

    1. A priest at my grammar school played the 'same birthday' game while trying to get our attention. While he was asking individuals about their birthdays to see if any others in the class of 50 had the same, I already knew the outcome. Jack Malooly and I were born the same day. I forget what point he made when his prediction was verified, but when remembering that day years later It struck me that the priest had access to our records and he probably knew what jack and I knew before he entered that class.

  4. The writer for CBS, Caitlin O'Kane, is a "digital content producer" covering "trending" stories for CBS News and its "good news brand, The Uplift." Content. Trending. Good News. Branding. OUCH...

    She specializes in those feel-good (or uplifting, if you will) stories that follow, or are interspersed among, the daily ration of bad and sad and miserably depressing stories labeled "news"...I guess the idea being that a spoonful of sugar helps the medicine go down. But too much sugar in one's diet leads to all kinds of other problems.

    I clicked on "The Uplift" but paused my mouse when I saw its "good news brand" is actually comprised of overlapping hearts. Above "content" along the lines of Dog Swims River, Hanukkah Meals, and Stuffed Animals for Seniors. Hard pass.

    Caitlin's original CBS story mentioned Luke and Hillary Gardner of Baldwyn, Mississippi, who also welcomed their son on their shared birthday, 27 years after they were born. BFD. I met my wife on a blind date on a Saturday, December 4. We were married on December 4, 27 years to the day. Co-inky-dink? Hell, no. I picked that date, a Friday. I've always had a long memory for dates and events. I definitely don't need that Prevagen memory supplement for geezers. I need the anti-Prevagen. If anything, my brain has too much memory. Can you tell?

  5. If you're obscure the rest of us are living under rocks! Admittedly she should have checked that number. Also admittedly I could have easily blown right past it and figured "yeah, OK." The important point is that walking through the math was entertaining and will make me think more clearly about odds and randomness next time.
    Re Anonymous's point about how it's not unusual at all for people to run into people you know out of town: So true. In fact, I lived on 6th Avenue between 11th and 12th with a roommate back in the day. She went home to Paris for a visit and ended up in a far-flung neighborhood where she had never been before, in a tiny restaurant in line for a table. The people in front of her, she could tell, were from NYC, and she started talking to them. They used to live in the Village too! What a coincidence, they used to live on 6th Ave! What a coincidence, they lived between 11th and 12th! Of course it turned out they lived in *our* apartment. But the odds are probably not all that interesting in reality.

  6. The only thing more fun than explaining probability to random people is the certainty of their eyes rolling back in their heads.

  7. Gosh, what a nitpicker! Can't imagine being that way. ; )

    Was going to say something similar to Andy's first paragraph. The likelihood that a couple who share a birthday gave their child-to-be's birthdate no consideration seems slimmer than 1 in 365...

    With regard to coincidence, I like to point out that, if you were in a sold-out Soldier Field and you found out the guy next to you getting a beer shared your birthday, you might be inclined to think "Wow!" But the odds are that there are 168 people in the crowd with your birthday.


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