[Symmetry]

You can't just sum up the huge variety of programs that was the New Deal like that. Yes, the National Industrial Recovery Act (NIRA) probably did halt the existing recovery but it was a recovery that FDR had started by reversing the hard money policies of his predecessors. And you can certainly argue all day about whether stuff like FDIC was a net improvement if you want to but that didn't really affect the length of the Great Depression.

We actually have a pretty good idea of what worked and what didn't during the Great Depression and mainstream economic historians[1] seem to have reached a rough consensus.

In school, though, we teach the Great Depression through the lens of political history. So for that purpose it doesn't matter what was really causing it, just what people at the time thought was causing it.

[1] I'm excluding Marxists, Austrians, MMTers, etc here.

[RugnirViking]

Don't tease us! We aren't all familliar with economic theory - what is the consensus on what worked during the great depression?

[Symmetry]

Really I'd recommend reading chapter 1 of The Wages of Destruction. The book is really on the economics of WWII but it summarizes the modern consensus on the Great Depression as a starting point and since it fits everything into one chapter ends up being very readable. Mostly it was contagious deflation mediated by the gold standard with gold hording causing deflation causing more hoarding. Countries on the silver standard like China were essentially unaffected. Countries that went off the gold standard early like the UK or Japan recovered early. The Wikipedia article is mostly a history of how economists' understanding of the Great Depression has changed over the decades rather than a description of where it stands now but it works pretty well.

https://en.wikipedia.org/wiki/Great_Depression#Mainstream_ex...

EDIT: A while ago Krugman had a very good piece trying to explain how deflation can cause problems. Different sorts of economists often disagree about whether its interest rates or aggregate quantities or expectation traps or whatever that's the most important aspect of tight or loose money but they all agree that these things are real and meaningful and generally explain depressions. http://www.slate.com/articles/business/the_dismal_science/19...