Blindly. People love to list them as evidence as if the numbers stand on their own. Reality is a person had some hand in assembling the numbers and there is no such thing as a bulletproof statistic. Good statistics ought to be scrutinized.
By training an algorithm that will have an impact on said statistics. Not only the algorithm can cheat (see Goodhart's law), but it can repeat biases that led to these statistics (like those law enforcement algorithms that became racists)
My favorite was the one they were training to detect cancer in imaging scans but they forgot to edit out the info stamp in the corner so it just started flagging all the scans from the cancer center!
You are describing Google Ads right now. Algorithms are better and better in reaching to poeple that are already on the purchase patch. It's like giving a restaurant flayers to people that are waiting for a weiter to show them a table.
Aren't our ads amazing? Look, almost everyone who saw them made the purchase!
Analytics that ignores Goodharts law ruin everything. Movies, HR, Marketing (not much to ruin left, but you get the point), performancet review, recommendations...
Averages. They're almost always a bullshit flag if it's tied to anything remotely political. If you're not going to also give the standard deviation and skew then at least use median.
...as a drunken man uses lamp posts — for support rather than illumination.
The question makes me remember Daryl Bem, a celebrated social psychologist. He published a much cited article called "Writing the Empirical Journal Article". About 15 years ago, he used this advice to prove that humans can see into the future. His advice is probably still used to teach. That's probably the worst thing you can do.
I once saw a reddit post where some busybody counted how many people with dogs walked by in an hour and multiplied that by 24 and assumed that was how many walked by in a day (as if it would be the same amount at all times of day)
Mixing up correlation with causation. A while back I was having a discussion here on Lemmy because people were saying pitbulls are dangerous and pointing to the disproportionate amount of deaths caused by pitbulls vs the percentage of dogs that are pitbulls. The argument goes something like this "Pitbulls are responsible for 55% of killings, but they're only 12% of all dogs, therefore Pitbulls are dangerous".
Oh, and BTW if you agreed with that argument above, congratulations, you're officially a racist, because those are the numbers of murder convictions and demographics for Black people in the USA. The argument is the same, and the reason why it's flawed is the same: correlation does not imply causation. Just because there's something seems disproportionate out of context doesn't mean it has the most obvious cause, in both cases the reasons are much more complex and mostly have to do with education and opportunity (or lack thereof).
Not making sure the result even makes sense. There was a real example, where a ~2010 news article said that the number of crimes in their city has been doubling every year since ~1980.
That is not possible. Assume that there was one crime in 1980. In 2010, there must be at least 2^20 crimes.