Um, whoops? It turns out that the Department of Labor underestimated job creation by record amounts over the summer. In total, from June through September, the Bureau of Labor Statistics missed 626,000 jobs.

It is standard for job growth numbers to be revised a month or two after they’re originally released, but these numbers are startling. Before the pandemic, the average month’s jobs number was adjusted by around 30,000. This summer, it was an average of more than 156,000 per month, and all in the same direction.

There were an estimated 850,000 new jobs in June—a massive number. But it was later revised upward by 112,000. July was even bigger, at 943,000. But it was later bumped up by even more: 148,000.

August came as a huge disappointment, with just 235,000 new jobs. But it has since been revised upward by 248,000. September was an even bigger disappointment, at 194,000. Since then, another 118,000 have been added. August and September were weaker months than the boom of June and July. But August, at least, wasn’t the enormous slump it initially seemed to be. And with October’s job growth coming in at 531,000, September would have looked like a blip if August hadn’t also looked so bad.

During the period of time for which jobs numbers were underestimating growth, polls found approval of President Joe Biden’s handling of the economy dropping from 51% to 39%.

The coronavirus pandemic has presented unprecedented challenges to the economy, and with them, unprecedented challenges to the people who track how the economy is doing. In March and April 2020, the BLS had to dramatically revise jobs numbers down, and the agency also found a misclassification error early in the pandemic that was causing it to understate the unemployment rate.

The integrity of the Bureau of Labor Statistics has always been seen as unimpeachable, and there is no doubt that it’s been faced with unpredictable waves of economic crash and resurgence even as the bureau’s statisticians cope with the same pandemic-induced alterations to their lives that everyone else in the country has had to handle. But boy. That’s a big and politically consequential mistake to have made four months in a row.