Left-Handers Day Turns 50 on Thursday — "Left-Handed People Die Nine Years Younger" — Woody Magazine, Aug. 10, 2026
Left-Handers Day Turns 50 on Thursday — "Left-Handed People Die Nine Years Younger"
The claim ran in the New England Journal of Medicine in 1991 and has come back every August 13 since. The arithmetic has never once been wrong.
- The 1991 paper behind "left-handers die nine years younger" measured not lifespans but the changing rate of left-handedness across generations. Assume identical lifespans for everyone, run the 1991 calculation, and the statistics still print the same nine-year gap.
- Unemployment rates and average wages move the same way. Give up the job search and you drop off the unemployment roll; lay off the low-paid and the average wage of everyone remaining rises.
- WeWork sold $702 million in bonds on a metric that turned a $933 million loss into a $233 million profit by striking marketing and administrative costs off the expense list. The rules of the list move before the averages do.
Three days from now, on Thursday, the world marks International Left-Handers Day — fifty years after the first one, which Dean R. Campbell, founder of Lefthanders International, declared in 1976. And every year, right on schedule, one sentence makes its rounds: left-handed people die nine years younger than right-handed people. Most of us have heard it at least once.
Its credentials are excellent. The claim appeared in the New England Journal of Medicine in 1991, and The Washington Post ran it as a headline the same day. Left-Handers Day coverage was still repeating it well into the 2000s. A pedigree like that earns some trust. Fair enough. The arithmetic holds, too. In the study, left-handed decedents averaged 66 years at death; right-handed decedents averaged 75. Subtract, and you get nine. For thirty-five years people have checked that subtraction, and it has never once failed.
The trouble sits one step earlier. The paper never measured how long left-handers live.
A Survey Mailed to 987 Families
In 1991, the psychologists Diane Halpern of California State University and Stanley Coren of the University of British Columbia surveyed the families of people who had died in 1989 in two Southern California counties. The returns covered 987 of the dead. One question did the work: which hand did the deceased use? Sorted by hand, the answers averaged out to 66 and 75, and the authors supplied an explanation — a world built for right-handers injures the left-handed. It sounds reasonable. Scissors, turnstiles, and power tools do favor the right hand.
The University College London psychologist Chris McManus suggests putting one more question to those same families. Did the deceased read Harry Potter? Average the answers, and the Potter readers will come out decades younger than the non-readers. Not because reading kills. Because the book's readership is young. Inside a death roll, a group's average age gets dragged toward whenever that group was born.
2.5 Percent of Those Born in 1902; 12.6 Percent Born in 1965
Left-handers were exactly that kind of group. In 1986, National Geographic tucked a survey card into the magazine, and 1,177,507 readers mailed it back. On the handedness question, about 6 percent of the elderly reported being anything other than right-handed, against 12 to 14 percent of the young. By American birth year, 2.5 percent of those born in 1902 wrote left-handed; among those born in 1965, 12.6 percent did. Schools and parents in the early twentieth century retrained left-handed children, and those children grew up right-handed — on paper, at least. As the pressure lifted, the rate climbed steadily with birth year.
Now return to the 1989 death roll. Getting into its left-handed column carried one requirement: being born late. In the early cohorts, hardly anyone had been recorded as left-handed in the first place. Why that produces a gap becomes obvious once you shrink the world to two generations.
Say 1,000 people born in 1900 died in 1989, at age 89, and 100 people born in 1960 died the same year, at 29. Assume hands have nothing to do with lifespan. At the rates their cohorts actually reported, 25 of the 89-year-olds count as left-handed, and 12 of the 29-year-olds do. Now split the roll by hand, as the paper did, and take each column's average age at death. The right-handed column holds 975 people who died at 89 and 88 who died at 29 — average, 84.0. The left-handed column holds 25 at 89 and 12 at 29 — average, 69.5. That is a gap of 14.5 years, in a world where nobody's hand cost them a single day.
Both columns are mostly old. But the young dead make up under a tenth of the right column and nearly a third of the left, and an average follows shares, not headcounts. Feed in every cohort from 1900 to 1988 and the real distribution of deaths, and the gap comes to nine years. What produced it was never the left hand. It was the rule for getting on the list.
Count Only the Dead, 25 Months; Count Everyone, Zero
A doubt survives all this. What if old left-handers are scarce precisely because they died young? The original authors defended their finding on exactly those grounds — the shortage itself, they argued, was the evidence. It sounds fair. The roll alone cannot tell the two stories apart.
There is a way to tell them apart: count the living too. English cricket turned out to be ideal material. A cricketer's bowling arm sits in the records from his playing days, so nobody has to rely on a family's memory. In 1993, a team led by the Durham University psychologist John Aggleton opened a cricket encyclopedia. Their sample was the 3,165 players already dead. The 2,580 right-arm bowlers had lived to an average of 65.62 years, the 585 left-arm bowlers to 63.52 — a gap of 25 months, too large to pass for chance. It looked like the nine-year study in miniature. One detail deserves attention. The team knew that 2,314 players in the same book were still living, and printed that number in the paper. Then they left them out of the calculation. Counting only the dead was not a metaphor; it was a choice the researchers made. The statistician Martin Bland wrote to Aggleton to press exactly that point, and Aggleton accepted it. The next year the two returned to the same source and assembled 5,960 players born between 1840 and 1960 — 3,387 dead and 2,573 living, together. This time the gap vanished. One signal remained — left-handers were likelier to die by accident or in wartime, for reasons the study could not establish. But a nine-year gap in lifespan showed up nowhere.
In 2023, the machine got its blueprint. Researchers at Microsoft's AI for Good lab and the Harvard T.H. Chan School of Public Health ran a simulation. They pinned the death-age difference between left- and right-handers at exactly zero, fed in only the generational change in rates, and redrew the 1989 dead. Then they ran the original paper's own calculation on that sample: split by hand, subtract the averages.
Then they erased the rate change and ran it again. The gap collapsed to 0.02 years. No individual's lifespan differs, and yet the column averages print nine years whole. Medicine has been caught by the same machine more than once. Papers finding that anesthesiologists, or women doctors, die young turned out to be measuring fields that had lately filled with young recruits.
That settles a thirty-five-year-old error. But this machine was never reserved for left-handers. The same part turns inside numbers we are handed every month.
The Month 20.5 Million Jobs Vanished, the Average Wage Jumped
Start with the unemployment rate. When it falls, life is getting better — mostly true. But being unemployed has an entry requirement. Under the standard that labor-force surveys share worldwide, the U.S. Current Population Survey included, you count as unemployed only if you actively looked for work in the past four weeks and could start at once. Someone who searches, tires, and stops — a discouraged worker — leaves the column. The survey files them under "not in the labor force" instead. So the unemployment rate can fall without a single job being created. That is no conspiracy. The statistical agencies say it themselves.
That is why one survey feeds two podiums. The side presenting its record reads out the unemployment rate; the side interrogating it reads out the employment ratio and the count of discouraged workers. Both are true. They differ only in which column they choose to read.
One month showed how far this machine can go. In April 2020, as the pandemic hit the United States, 20.5 million jobs disappeared in thirty days. Unemployment leapt to 14.7 percent, the largest one-month rise since records began in 1948. Yet in the same release, the Bureau of Labor Statistics reported that average hourly earnings had climbed $1.34, to $30.01. The month before, the gain had been 15 cents. Wages did not surge in a disaster month. The layoffs fell hardest on low-paid work, the cheapest rows emptied out of the payroll list wholesale, and the average of everyone remaining floated upward. The bureau wrote that caution into its own release. Nobody's wage rises, and the average wage rises. It is the 1989 death roll, running again.
A Company $900 Million in the Red Builds a Profitable Metric
In the hands of a company that wants your money, the machine gets more refined. In 2018, WeWork, the co-working firm, needed to open its books to sell bonds — the certificates a company issues to borrow from investors. The books were the problem. Revenue in 2017 came to $886 million; the net loss came to $933 million. The company lost roughly what it earned, and nobody lends happily on that.
WeWork's solution was to rewrite the expense list. EBITDA, a standard supplementary gauge, shows earnings before interest, taxes, depreciation, and amortization — a rough read on whether the operation itself runs. WeWork went several steps further, striking marketing, general and administrative, and design and development costs from the expense column, and named the result "community adjusted EBITDA." On that metric, a company more than $900 million in the red became a company $233 million in the black.
The analysts had never seen it; the market bought it anyway. WeWork had planned to issue $500 million; orders came in at roughly five times that, and the company raised the offering to $702 million. The next year, WeWork carried its books to the stock market, which reread the list, and the offering collapsed. In 2023, the company filed for bankruptcy. "Adjusted" was not a lie. It was a pointer, aimed at the list rather than the math: which costs get to count.
The calculator is innocent. Seventy-five minus sixty-six, the unemployment division, WeWork's addition — the sums all check, and that is exactly why they live so long. People who check the work check the sum and never the list. For thirty-five years, plenty of people re-ran the nine; almost nobody counted how many left-handers were born around 1900. So when an average moves sharply, what separates readers is not arithmetic but a single question. Did the people change, or did the list? Three days from now, the nine-year gap will come around again. Anyone who has looked at the list reads it differently.
- Source ↗ Lavista Ferres et al., "Modeling to explore and challenge inherent assumptions when cultural norms have changed," Archives of Public Health (2023)
- Source ↗ Aggleton et al., "Handedness and longevity: archival study of cricketers," BMJ (1994)
- Source ↗ Aggleton, Kentridge & Neave, Journal of Epidemiology and Community Health (1993)
- Gilbert & Wysocki, "Hand preference and age in the United States," Neuropsychologia 30 (1992)
- Source ↗ The Washington Post, "Left-Handers Die Younger, Study Says" (Apr. 4, 1991)
- Source ↗ U.S. Bureau of Labor Statistics, "The impact of the COVID-19 pandemic on the Employment Situation for April 2020"
- Source ↗ WeWork Companies Inc., SEC filing (definition of community adjusted EBITDA)
- Source ↗ Global Finance, "WeWork Works Bond Market Despite Unusual Accounting Practices" (2018)
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