What is useful and not so useful in economics.

A recent post at Econ Browser analyzes unemployment using Okun's law - a topic usually found in introductory macro courses. The useful . . . from the conclusion:

This leads us to conclude that there has been indeed an effect of the Great Recession on the long-term employment. Specifically, on average, since the exit of the recession (2009q2), we get that the employment is 2.7 % below its potential level (according to the non-linear ECM), meaning that, from a structural point of view, around 3 millions of jobs have been lost after the recession.

OK, a nice conclusion and useful information to consider - a number of interesting questions are raised.

OK, not so useful.

Additional remark:

As in the linear framework, it is noteworthy that a non-linear model estimated in differences, that is without integrating a long-term relationship, also leads to unrealistic results. This underlines the usefulness of having the long-term relationship into the model.