(Bloomberg View) — A lot has happened in America this year. But economics columnists might well dub this "the Year of the Minimum Wage."

The year started off with a hike to $15 an hour in the area around Sea-Tac Airport; by June, Seattle's City Council had followed suit, passing a similar increase that phases in gradually. Chicago is raising its minimum to $13 an hour. Los Angeles has been considering going to $13.50, though so far, it has only raised the minimum wage for hotel workers (hotel owners sued). Various other state and local legislatures have either enacted, or are considering, hikes.

So it's not surprising that we've spent a lot of time talking about the minimum wage this year. What's surprising is how we've been talking about it: confidently, as if we know for sure what will happen when these laws take effect. Mark Bittman, my favorite food writer, has boldly opined that "the credibility of those who argue that employers 'can't afford' to raise pay … is nil." Liberal journalists crudely eyeball statistics and proclaim that the idea that minimum wages can kill jobs have been "debunked"; conservative pundits equally claim to have debunked the debunkings.