Uncertainty and asymmetric risks

Justin Wolfers says Charles Plosser is being a bit silly on the Freakonomics blog.

Specifically he says that:

  1. Plosser says we should tighten more quickly than estimates of “slack” suggest, as the level of slack is uncertain,
  2. However, since slack is uncertain it could be higher or lower – so this doesn’t make sense unless you weigh the outcome with lower slack more highly than the outcome with higher slack, which seems wrong!

Now I think he is being a bit sneaky here.  Yes there is uncertainty, but the perceived ex-ante risks around this uncertain variable are asymmetric.

What the hell am I trying to say here?  Well, we know that potential economic activity seems to be “trend stationary” over time (so it tends to rise at an average rate), however we aren’t quiet sure of the trend.  When we measure “slack” in a “recession” we are normally coming off a high point – which biases up our trend estimate.  Macroeconomists do heaps of stuff to try and correct it – but we often end up with a higher estimate than seems fair.

As a result, even though slack is uncertain there is a greater likelihood that slack will turn out to be smaller than it is currently thought to be rather than larger.

Of course, on an unrelated note I would say that economists should look at the unemployment rate as a measure of slack a lot of the time – as we have a measure of it, and it does give us an indication of the relative “hole” in the economy.  With unemployment over 10% the US should still be looking at substantial stimulus – so Plosser seems a little gun ho.