Many factors influence a county's crime rate or average health. Some, like lead exposure and the quality of local governance, aren't surprising, but a new paper raises one you probably didn’t expect: how many post offices it had more than a century ago.
At the time of the US revolution, there were just 75 post offices in the 13 colonies, but as early as 1792 the new nation identified expanding the postal network as an important factor in holding a far-flung nation together. In 1841, almost 80 percent of civilian federal employees were postmasters.
Dr Jeffrey Jensen and Dr Adam Ramey of New York University were interested to see how these choices shaped the growing country long after some of the offices had been shut down. They tested correlations between the number of post offices a county had, per resident, in 1890 against a wide range of modern measures.
Besides population number, Jensen and Ramey controlled for other 19th-century factors that might have a lasting legacy such as the racial mix, manufacturing output, length of railways, and even turnout in presidential elections of the era.
Even after allowing for these possible confounders, Jensen and Ramey report in Proceedings of the National Academy of Sciences being well supplied with post offices 130 years ago strongly correlates with suffering fewer crimes, particularly rapes and murders, per capita today. People in these old post-office towns are also less likely to die young and were more likely to have voted in the 2012 presidential election (2016 voting wasn't tested).
The link between these measures may seem so obscure it is easy to dismiss this all as a spurious correlation, like those between pool drownings and Nicholas Cage films. Correlation, after all, does not equal causation.
However, the authors have an explanation for why the influence of post offices could be so lasting. Local newspapers tended to be established close to post offices. In the days when mail and telegrams were collected at the post office, it was hard to run a paper without being nearby. The presence of local newspapers limited local government corruption and helped strengthen what sociologists call “social capital”, measured by things like the number of civic, social, and non-profit organizations in an area.
Social capital has long been used to explain why some areas are healthier and have less crime than others, but that raises the question of how the social capital was acquired in the first place. Jensen and Ramey propose government investments such as post offices provide a significant part of the answer.
With the postal service struggling to compete commercially as technology changes, America is debating whether the government should bail it out or let it go under. The implications for 2150 don't seem to be considered.