Do Political Yard Signs Even Work?

I told people on Monday that I thought Jack Ciattarelli would do better in the race for governor of New Jersey than the polls were indicating. My unscientific rationale was that Mr. Ciattarelli, the Republican challenger, had many more lawn signs than Gov. Phil Murphy where I live, northeastern Bergen County. I would estimate that Mr. Ciattarelli had at least 10 times as many signs.

Mr. Ciattarelli did lose, but by only about 1 percentage point, defying a Rutgers-Eagleton poll showing him 8 percentage points down in late October. That didn’t make my lawn sign theory correct, of course. But the result was surprising. So I decided to look into the matter more closely.