And lo, it began: The celebratory ringing in of a new year and, some said, a new decade. Only to be quashed by those who pointed out that *ahem* Actually, no, a new decade starts when the year ends with a one, not with a zero.
But there’s more to it.
It’s correct to say that counting things doesn’t start with a zero. When counting to ten on our fingers, for example, we start with a one and we go to ten. Likewise, when counting the years since someone was born, as we do with our calendar years (spoiler alert: It was Jesus), you don’t count starting with a year zero. You count starting at one year of age.
So it’s accurate to say, as the pedants argue (as I have), that a proper, calendar decade is between years XXX1-XXY0. Thus not between 2010-2019, with the new decade starting in 2020, but rather, between 2011-2020, with the new decade starting in 2021. That’s the literal view.
Ah, but…
BUT…
But…
It’s equally as valid to say that a decade is ten years starting from wherever you choose to start it until ten years later. And more to the point, we do refer to past sets of decades, particularly named ones, with regard to the first digit of that set of ten and not the last (“the roaring 20s”, “the dirty 30s”, etc.). Meaning that in retrospective parceling, we do count the zero year as the the first year of that set. That’s what is ultimately a more practical view.
No one practical is going to argue that, for instance, “the roaring 20s” went from 1921-1930. That would be true, but no more true than to say that 1920-1929 is the decade they’re referring to, which inherently means that 1930 would be the start of the following decade.
So I say it’s time to drop the pedantry. 2010 to 2019 is as valid a full decade as any, and if people want to count 2020 as the first year of a new decade as their reference point, let them, because you can rest assured that people in the future will anyway.