Feast or fiction?

Turkey math vs. Trump math

When the American Farm Bureau Federation releases its annual Thanksgiving Dinner Cost Survey one day soon, it will receive more than the usual amount of attention.

That’s because Donald Trump recently took to bragging, rather creatively, about Walmart’s “Thanksgiving bundle,” which supposedly serves up a feast for about $40—that’s 15 bucks cheaper than last year.

Sounds great until you read the fine print: This year’s “bundle” is seven items lighter and skimps on name brands. So no, it’s not exactly an apples-to-apples comparison—more like turkey-to-turkey-ish. Walmart is helping us tighten our belt. Mr. Trump seems blissfully unaware or willing to disguise the truth. Imagine that.

The Farm Bureau’s take, by contrast, will be based on actual math instead of marketing. Last year, it found the average cost to feed 10 people the traditional spread was $55.08, down about five percent from the year before—no downgrades, just data.

We’ll see whether Mr. Trump still wants to take a victory lap around the kitchen table once this year’s grownup data are served up and reported on.

Reality may not go down quite as smoothly.