This question arises from recently reading the Daily Article by Mark Thornton.
If you assume that interventionism is always bad for the economy (the Interventionist Hypothesis), and Hoover was an interventionist, then the economy under Hoover would have gone bad. Which it did.
Hoover's administration was followed by Roosevelt who was also an interventionist. Therefore, one would predict that under FDR the economy would have gone even worse. But it didn't. On some measures it improved.
Doesn't this discredit the Interventionist Hypothesis?
I would say a decade of depression is worse than a few years - it was FDR's policies which continuously thwarted the economic activities of his subjects.
You're assuming an instantaneous relationship between policy and economic health. Growth in Year X is not due to policy in year X, but is due to all the things that have ever happened in the economony... You can also argue the reverse causality - that higher economic growth allows countries to raise taxes because people won't be as ticked off since they're getting richer.
Unless I am mistaken, Hoover was battling the depression for 3 years, and FDR for even long than that. So there was plenty of time to assess the effectiveness of their respective policies.
Nonetheless, under FDR there were improvements. But there weren't under Hoover. Yet they were both interventionists, indeed FDR may have been a bigger interferer than Hoover.
I agree, cause and effect never occurs over a longer period than 3 years ...