Have you found conflicting information about ancestors' birthdates? (Join the club!)

In today's "Letter from Ireland," Mike Collins illuminates why recorded dates may differ. You'll want to read the entire article here, but following is an excerpt from his fascinating explanation:

...The World When Dates Were Flexible

Picture rural West Cork in the late 1850s. My great-grandmother Collins is born on a small farm in the middle of the night. Thankfully, the baby arrives healthy.

A few days pass or maybe longer. Life on the farm continues, cows need milking, turf needs cutting, neighbours call in. When would they have gone to the church for the baptism? When the mother felt strong enough. When the weather allowed? When they could spare the cart?

The baptism happens when it's convenient. That’s the date the priest writes in his register, because that’s the day he performed the sacrament. Birth date? The parents might have said “a fortnight ago” or “around the last full moon.” The priest wrote what he knew for certain.

A few years later, civil registration finally arrives, but many families simply carry on as they always did, relying on memory rather than paperwork.

Fast forward to 1901. A census enumerator arrives at the door. “Age?” he asks.

Does she know her exact age? She may never have celebrated a birthday in the modern sense. Someone in the house might call out, “She’s in her forties, near enough.” The enumerator writes it down. If she’s actually forty-two and a half, it doesn’t matter much until a genealogist a century later starts reverse-engineering birth years.

And by 1911 there was another complication. The Old Age Pension had been introduced a few years earlier, payable from age seventy. Suddenly age mattered in a way it never had before. Some people genuinely didn’t know their exact birth year. Others quietly added a year or two to qualify for the pension. That’s why many families appear to age faster between 1901 and 1911 Irish census than the calendar allows...