The U.K.’s Office for National Statistics used to knock on doors and ask people if they were employed, as a traditional way of compiling the country’s labor market data.

But when COVID-19 forced social distancing in 2020, door-knocking was out. At one point during the pandemic, the survey was reliant on how many phone numbers it could find for a representative sample — and also on people actually answering their mobile phones when an unknown number called. Only a quarter of Britons say they answer such calls, with most wary of scams. Fewer than half of U.K. households have a landline, and those numbers can be difficult to find.

Response rates plunged. By 2023, the data had become so patchy, the ONS was forced to suspend its unemployment reading as it desperately sought to repair a key release that helps inform government policy, influences interest rates and drives billions of dollars of investment decisions. An ensuing crisis of confidence in Britain’s data ended with the resignation of its national statistician, Ian Diamond, last month, following fierce criticism from politicians and senior central bankers.