Oh rats! Food safety inspectors are more lenient toward restaurants as the day goes on

The “daily schedule effects” described in the paper are almost comically relatable: If a health inspector has to inspect a particularly nasty (in report-speak, “worse compliance or greater deterioration in compliance”) kitchen, she’s more likely to slap a few extra violations on the next kitchen she visits. There’s even a statistic attached to this phenomenon: each additional violation in the first inspection increases the number of violations in the next restaurant by 1.5 percent. We here at NFE feel very badly for whoever drew the time slot after our notorious neighborhood Chick-fil-A, which earned a whopping 59 violation points—31 points past the “C”-grade threshold.

On the other hand, a late-in-the-day inspection may also come with its own benefits. Like pretty much everyone, health inspectors like leaving the office on time, and they get tired as the day wears on. That means the average number of violations they’re likely to cite falls by 3.2 percent with each new inspection throughout the day. And “potentially shift-prolonging inspections,” like a 5:30 commercial kitchen visit, for example, exacerbate the fatigue factor even further. Those inspections yield 5.1 percent fewer citations than the first in the day.

Decision bias impacts other professions, too. Judges tend to get make stricter decisions toward the end of the day, and baseball umpires are more likely to call a “ball” right after they’ve called a “strike,” and vice versa. But the Harvard researchers Maria Ibanez and Michael W. Toffel write that the decision biases they observed in restaurant data happen at a higher rate than in courtrooms and on the baseball field. They found that restaurant inspectors’ biases are similar in magnitude to just one other group of professionals who have been studied in the same way: Loan review officers.

Ibanez and Toffel write that these biases could be eliminated with some pretty simple changes. Managers could cap inspectors’ daily quotas to ensure they stay sharp, or schedule administrative tasks for end of day so the last inspection doesn’t get the short end of the stick.

In the meantime, there’s no need to stop eating at your local sandwich shop for fear of a sleepy inspector missing a giant rat’s nest. These guys still cite, on average, two or three violations per inspection. At worst, the 5 percent “hanger”-related dip inspectors experience probably only means they end up missing the improperly stored dishwashing soap bottles in four dozen restaurants out of a thousand.

Or maybe that’s just what we prefer to believe.