How long would the depression have lasted without any intervention

I understand this may be a little economically controversial, but assuming no "new deal" style intervention, basically a continuation of the hoover policy, how long would the depression last?
 
I understand this may be a little economically controversial, but assuming no "new deal" style intervention, basically a continuation of the hoover policy, how long would the depression last?

Technically speaking a depression is a period of more than 2 consecutive declines in economic growth, that ended in 1934 (33 for most European countries) when the (US) economy started growing again.

But relative to 1929 it might have been shorter actually, a good deal of the problems were caused by the tightening of monetary and fiscal policy; take for example the Banking Act of 1935 under Roosevelt that helped neuter the recovery that was underway by the time he took office in 1934 (that he had little to do with). This was still an era where many monetary institutions appointed by governments were running the old gold-standard with deflationary policies as opposed to anything proactive or Keynesian; it was debatable how much good the New Deal did as opposed to how badly did the federal reserve shoot the recovery in its infancy.
 
The key here is getting rid of the Gold Standard:

400px-Graph_charting_income_per_capita_throughout_the_Great_Depression.svg.png


In defence of Hoover, he was actually engaging in some small-scale interventionism. President Coolidge would have been far worse.
 
Yeah, regardless of what you think of how Bernake handled the 2008 financial crisis, it's pretty telling that one of the options on the table was not "TIGHTEN THE MONEY SUPPLY AT ALL COSTS!!!!!" Andrew Mellon was downright awful on this one.
 
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