Whenever you try to force the real world to do something that can be counted, unintended consequences abound.
Seduced by their seeming precision and objectivity, we can feel betrayed when the numbers fail to capture the unruliness of reality.
The trouble arises whenever we use numerical proxies for the thing we care about.
Numbers can be at their most dangerous when they are used to control things rather than to understand them.
To simplify the world enough that it can be captured with numbers means throwing away a lot of detail. The inevitable omissions can bias the data against certain groups.
Numbers don’t lie, except when they do.
Once a useful number becomes a measure of success, it ceases to be a useful number. This is known as Goodhart’s law, and it reminds us that the human world can move once you start to measure it.
Deborah Stone writes about Soviet factories and farms that were given production quotas, on which jobs and livelihoods depended. Textile factories were required to produce quantities of fabric that were specified by length, and so looms were adjusted to make long, narrow strips. Uzbek cotton pickers, judged on the weight of their harvest, would soak their cotton in water to make it heavier. Similarly, when America’s first transcontinental railroad was built, in the eighteen-sixties, companies were paid per mile of track. So a section outside Omaha, Nebraska, was laid down in a wide arc, rather than a straight line, adding several unnecessary (yet profitable) miles to the rails.
It’s possible for two things to be true: for numbers to come up short before the nuances of reality, while also being the most powerful instrument we have when it comes to understanding that reality.