Karl Smith writes (sorry for quoting half the post):
Sometimes the net return-to-action is positive over the entire relevant range. In those cases smart finely tuned action is worthless and getting the most bang for your buck is actively harmful.
You always maximize simply by going full throttle regardless of the cost. This is because marginal benefit always exceeds marginal cost over your range. Note that this will generally not be the point that maximizes the rate-of-return or “bang for the buck.”
Thus, getting the most bang-for-your-buck is the wrong answer.
This is the perfect realm for something like fiscal policy. Efficiency is not something that central governments are good at. On the other hand, really-freaking-huge, is something that central governments are good at it.
A depression, where idle resources are plentiful and real borrowing costs are zero or negative is exactly where you find almost no return to precision.
Indeed, Austrians might find comfort in my suggestion that a general crisis is almost by definition a time when “knowledge of the particular circumstances of time and place” has low value. This is both why strong governments can do a lot of good in crisis and why people are wrong to assert that “if government is so good at mobilizing for war, then surely it can manage making shoes during a time of peace.”
That gets things exactly backwards.
To boil down his premise as I see it, efficiency matters increasingly less the farther the economy gets from potential, as there are few, if any, individual actions that will return the economy to potential. I think this is a good simplification, but has some hints at oversimplification. If one thinks of recoveries as a chain of related or semi-related events and believes that there are many chains that can be used to achieve recovery, then targeting the shortest chain should be the goal. That may mean grasping at the first link in several chains to account for uncertainty (the public sector is not limited to one policy approach after all), but a slightly more targeted approach might be beneficial in selecting the proper chain of events. Of course I am oversimplifying the process of determining the shortest course of action to a recovery, but this is a blog.



