I feel like you're missing the most interesting point of this story - how many other policies are decided based upon nonexistent or erroneous data that nobody bothered to verify? You assume it's an anomaly, but what if this were the norm?

My post was in no way meant to be exhaustive but it's good to know that since you failed to list any of my other shortcomings in life that you believe me to be otherwise perfect. Afterall, you failed to list all of my failures so you must be assuming they don't exist.

My reasoning was that if you thought it were the norm, it wouldn't be worth mentioning. And you talk about it as a 'most interesting' example so it seems unlikely you didn't consider it an anomaly.

they mentioned that

OP mentioned one error and the resulting policies because of it, I didn't see any others he mentioned. I don't think it's reasonable to know how many policies are determined based on sound data and processes, and how many are so politically motivated that nobody ever checks the numbers. You really only find out by happenstance when someone checks on a lark. We could make a concerted effort to verify everything, but where would you even begin for policies that have already existed for decades?

If I remember correctly, this wasn't really a "mathematics" mistake. The formula simply wasn't applied to the right number of cells (they didn't apply the cell-selection far enough).

Although that's beside the point. This was a tragedy of the academic economist profession, and should be covered day-one in any Econ research class.

It is a very famous example in economics, but it was very unusual for them to do their analysis in Excel rather than a stats package like Stata.

It's not that no one bothered. They didn't share their data with anyone for some time. As soon as they did, the mistake was immediately discovered.