We look to be headed for what could be the most unpopular sequel since “Home Alone 3”: Biden versus Trump 2.0.

One question goes to the heart of shaping expectations for that matchup: Why does everyone think the economy stinks? The answer is critical, given that this election is probably going to be close and that a variety of research suggests that the incumbent party’s chances are better when the economy is going well. President Biden, trailing Donald Trump in early polls, will need all the economic tailwind he can get.

Many commentators on the left have focused on a purported gap between what they see as objective data signaling a strong economy (in particular, persistently low unemployment) and middling to poor consumer sentiment, as in the University of Michigan’s monthly survey. This gap is sometimes attributed to partisanship — Republican voters being unwilling to give any credit to Mr. Biden — and at other times to media bias or misinformation driven by social media.

But a more careful look at the numbers reveals a different answer, and it requires no great mystery to solve, no inexplicable gap in the data.