Is it possible our (excellent) colleagues over on the printing presses accidentally ran our column in place of the horoscopes one week? Because all of a sudden, you’re all asking us about astrology.
For example, Leah Loeffert in Annandale, Virginia, noted everyone she meets in D.C. seems to be a Virgo; she asked if folks who share an astrological sign tend to congregate in certain places. And Emily in Maryland noted that five out of six of the people on her team at work are Cancers, and asked if people with certain signs cluster in certain jobs.
Early this year, our friends at YouGov collected the Zodiac signs of more than 35,000 Americans. It had some fun clues. Construction workers leaned Taurus (May), the “builders of the zodiac,” teachers were inquisitive Gemini (June), and I.T. workers were Capricorns (January) — all of which would probably make perfect sense to us if we’d called an astrologer.
But there was a catch. Even that unusually large survey had trouble getting differences that far exceeded the margin of error, so we’d have been asking the astrologers to find significance in randomness. And we’re sure nobody would want to put them in that position!
Instead, we called in the big guns. The Census Bureau’s American Community Survey is roughly on the order of 100 times the size of YouGov’s mammoth sample, which itself is about 10 times bigger than your typical political poll.
Our always-cautious Census comrades don’t release respondents’ dates of birth for privacy reasons, but they do tell us the three-month quarter in which each person was born. And alone was enough to draw into question the stars’ power.
It showed a delightfully dull distribution, with the share of each major occupation being born in each quarter rarely differing from the norm by more than a couple percent. But our towering two-decade dataset drip-fed us enough anomalies to keep our curiosity at least partially piqued.
For example, maintenance workers, janitors, construction workers and truckers/drivers are all a bit more likely to be born early in the year, while office-support and financial workers tend to be born in the later half of it.
For monthly detail, we experimented with data from the 1900 Census and the Social Security Administration, back when the Census asked when you were born, but we simply couldn’t get reliable enough data from an era where not everybody even knew their age with that much precision. In desperation, we turned to one of our favorite sources: the almighty voter file.
U.S. voters usually supply their date of birth when they register to vote. States then publish much of that registration data as part of the long-running and successful American effort to prevent voter fraud through transparency. The published data doesn’t always include birth dates, again for privacy reasons, but our friends at L2 use other sources to ensure we have birth dates for about 174 million U.S. adults.
In terms of occupations, we do see tiny variations. Farmers and blue-collar workers are more likely to be born early in the year and folks in the military are more likely to be born early in the year, peaking in Capricorn (January). Lawyers and creative types are a bit more likely to be to be Tauruses (May) while financial professionals tend slightly toward Virgo (September) and civil servants lean toward Cancer (July) — though we’ve personally never found them to be crabby at all.
But take that occupation data with a grain of salt, since it’s estimated by L2 rather than reported by voters. The file’s a bit more conclusive on other questions.
Most notably, with a few adjustments to remove obvious anomalies — there’s little chance Jan. 1 is actually the most common birthday in U.S. history — the voter file gives us decent estimates for the birthdays of a huge chunk of the U.S. population.
That data tells us the most common zodiac signs, once we adjust for some anomalies in the data, seem to be Virgo (September), followed by Cancer (July) and Leo (August). We’re using the Astrology.com date ranges since that’s what powers The Post’s horoscopes — others may differ by a day here and there.
The dominance of those three signs is due, of course, to their position astride the three most common birth months: August, September and July, in descending order.
The most common birthdays are tougher to pin down. They bounce around year to year, since American birth rates jump by about 50 percent on weekdays according to our analysis of recent data from the Centers for Disease Control and Prevention. That’s because Cesarean births are more than twice as common on weekdays, especially during business hours, and induced vaginal deliveries are about 60 percent more common. In other words, if your hospital has the option to schedule your birth, it’s probably going to happen during the staff’s normal working hours.
To adjust for that, we can average over about eight decades. When we do that, the 10 most common birthdays in our data fall within the second half of September, with the 24th narrowly edging out the 25th for top honors.
The least common zodiac signs are Capricorn (January), Sagittarius (December) and Scorpio (November); they have the misfortune of falling near the Great Winter Birth slump.
The least common birthday is, of course, February 29. Other rare birthdays include the days around the popular religious holiday of Christmas and the popular secular holiday of July 4 — perhaps out of fear of the kid being derided as a real life nephew of their Uncle Sam?
But the sign’s relative popularity isn’t even close to enough to explain why reader Leah met so many Virgos in D.C. — after all, even the most common sign accounts for fewer than 1 in 10 Americans.
So, is there a geographic trend in play? Maybe! In America’s northern corners, Cancers (July) predominate, but as you travel south the birth peak hits lower on the calendar and Virgos (September) or even Libras (October) hold sway.
So, yes, Virgo (September) is one of D.C.’s most common Zodiac signs, along with Cancer (July). But each still only applies to 9 percent of the population. So why do we so often end up meeting so many people who share our sign?
Well, if you throw six 12-sided dice enough times, you’re going to end up rolling five of the same number eventually! Say the odds of rolling at least five matching dice are 1 in 3,700. Well, In D.C. alone, we have so many committees, confabs and klatches — far more than 3,700 — that it’s inevitable we’ll get at least a couple lucky dice rolls that’re predominantly Pisces or totally Taurus.
Hi! The Department of Data craves queries. Tell us what piques your curiosity: What are the most common words in horoscopes, overall and for each sign? Does legalizing marijuana reduce suicide rates? Did the single, enormous surge in births about nine months after the end of WWII skew the birthday data? Just ask!
If your question appears in a column, we’ll send you an official Department of Data button and ID card. This week we’ll send them to Leah and Emily!
The post The most common Zodiac signs (and birthdays) appeared first on Washington Post.
