That's not empirical study, it's statistical analysis of historical data. Which is useful, certainly, but it shouldn't be treated as the same level of certainty

That's not empirical study, it's statistical analysis of historical data. Which is useful, certainly, but it shouldn't be treated as the same level of certainty as empirical study and it shouldn't be confused for it. The article makes the distinction between the two very, very clear. Economics loves to play fast and loose with the definition of "empirical" tests, but almost none of the main theories of economics are empirically testable—because we simply cannot create new, controlled economies and run preregistered experiments against them. Instead, we have to make do with the data we have, and we can't generate more, and we have to deal with the amount of uncertainty that the analysis of existing data brings with it.