The Problem with Failing to Admit We Don’t Know
https://blogs.scientificamerican.com/observations/the-problem-with-failing-to-admit-we-dont-know/
In January 2018 the BBC News Web site announced that in the three months before November 2017, "UK unemployment fell by 3,000 to 1.44 million." The reason for this fall was debated, but nobody questioned whether this figure really was accurate. But forensic scrutiny of the U.K. Office of National Statistics Web site revealed that the margin of error on this total was plus or minus 77,000—in other words, the true change could have been between a fall of 80,000 and a rise of 74,000, and a more honest headline would have been "UK unemployment may have gone up or gone down."
Although journalists and politicians appear to believe this claimed decline of 3,000 was a fixed, immutable tally of the entire country, it was in fact an imprecise estimate based on a survey of around 100,000 people. Similarly, when the U.S. Bureau of Labor Statistics reported a seasonally adjusted rise in civilian unemployment of 69,000 from December 2017 to January 2018, this was based on a sample of around 60,000 households and had a margin of error (again rather difficult to find) of plus or minus 300,000. Unemployment counts based on surveys of businesses can also be subject to substantial revisions, such as the announcement in August 2019 that there were 500,000 fewer jobs than previously thought.