https://quillette.com/2022/12/08/how-do-they-know-this/
“If you take one point away from Bad Data it should be that the vast majority of statistics are estimates, some of them are very rough estimates, and statisticians are constrained by limited resources and bounded knowledge. It is not a crisis. Outright fraud is rare, but when confronted with an impressive statistic, especially when it seems surprising, it is worth asking, “How do they know this?” Very often the answer will be that they don’t really know it at all.”
A review of Bad Data by Georgina Sturge, 288 pages, The Bridge Street Press (November 2022)
H.G. Wells once predicted that “statistical thinking will one day be as necessary for efficient citizenship as the ability to read and write.” It was a slight exaggeration, but in an age of big data in which governments pride themselves on being “evidence-based” and “guided by the science,” an understanding of where facts and figures come from is important if you want to think clearly.
Georgina Sturge works in the House of Commons Library where she furnishes UK MPs with statistics. If Bad Data is any guide, she also provides them with caveats and other words of caution, which are ignored. This informative, reasoned, and apolitical book offers a string of examples to show that statistics are not always what they seem. Some statistics are rigged for political reasons. Others are inherently flawed. Some are close to guesswork. Even crucial variables such as Gross National Income and life expectancy are shrouded in more uncertainty than you might think. We don’t really know how many people live in Britain legally, let alone illegally. The number of people who are living in poverty varies enormously depending on how you measure it.
Crime and unemployment are hugely important to voters and therefore susceptible to manipulation by the authorities. England and Wales have data on recorded crime stretching back to 1857, but most crimes are not reported to the police and even when they are reported they are not necessarily recorded by police officers. Setting the police targets to reduce crime creates incentives for the police to allow possible crimes to go unrecorded. This has happened so much in Britain since the 1990s that the UK Statistics Agency stripped the recorded crime figures of their “national statistics” status in 2014.