Another shockingly good jobs report shows the U.S. economy is growing

The jobs number was more than double expectations on Friday, and December's data was one of several months that was heavily revised. Why are economists' predictions so often wrong?

It is impossible to say with certainty how much a country's economy as a whole grew or how many people were employed at a given time. Finding out how many new hires there are in a given month involves asking each employer how many people they have on their payroll. That's why government and other providers of economic data often rely on surveys to produce sophisticated estimates.

The BLS, the Census Bureau, and other government agencies that conduct surveys that inform economic reports do rigorous work to make better estimates from the information they collect. And often they do a great job at it.

But studies are, by nature, imperfect.

In the same way that election polls don't always predict the winning candidate, polls don't capture the exact true picture. However, they can be very close to the truth.

In Election polls And government surveys have a sample size of respondents designed to be representative of the group being studied. The larger and more diverse a sample is, the closer an estimate will be to the true value.

To obtain a large and diverse sample, BLS and other agencies require a lot of outreach to recruit people to be part of a group that regularly lists them to respond to a given survey. The recruitment rate for surveys used in many of the BLS's monthly reports, including employment, the consumer price index, and job openings and labor turnover, has fallen sharply from pre-pandemic levels.

But Laura Gelder, branch chief of national estimates within the BLS' current employment statistics division, told CNN that these declines can be attributed to a variety of challenges, such as the voluntary nature of participation in surveys and survey fatigue — meaning people are bombarded with too many surveys.

There are also changes in technology, such as caller ID and spam filtering, and increased concerns about confidentiality and data security.