Scholars have not agreed on the exact causes and their relative importance.
The search for causes is closely connected
to the question of how to avoid a future depression,
and so the political and policy viewpoints of scholars
are mixed into the analysis of historic events eight decades ago.
The even larger question
is whether it was largely a failure on the part of free markets
or largely a failure on the part of government efforts to regulate interest rates,
curtail widespread bank failures,
and control the money supply.
Those who believe in a large role for the state in the economy believe
it was mostly a failure of the free markets
and those who believe in free markets believe
it was mostly a failure of government
that compounded the problem.
Current theories may be broadly classified into three main points of view.
First there are the monetarists,
who believe that the Great Depression started as an ordinary recession,
but that significant policy mistakes
by monetary authorities (especially the Federal Reserve),
caused a shrinking of the money supply
which greatly exacerbated the economic situation,
causing a recession to descend into the Great Depression.