The most frequent causes of economic downfall? In retrospect what are the major parameters, most frequently causing countries' economy to reduce its size and/or growth.


Global Financial Crisis?
Regional instability?
Local Banking Sector failure?
Long-term inefficient governmental fiscal, civil, law policies, corruption?
Interestingly, Romer and Romer (2014) show that financial crises are typically not causing major downfalls in economic activity, if you restrict your sample onto the developed countries post WWII.

An advantage of their method is that they look at a real time narrative, so they don't try to judge ex-post what was a crises. So historians winner writes history criticism doesn't apply here.

It is certainly worse if the financial crises is global, but that's pretty infrequent.