Tyler Cowen doesn’t much.
I tend to agree with Cowen. Nominal rigidities were quite the thing just before I arrived, so I think they are over rated. However, there are two points one of which is totally twitty and the other of which is a dead horse still being beaten by Paul Krugman.
OK twitty: By definition for there to be unemployment there must be three agents, an employer, an employee and an unemployed person. The unemployed person must be eager to work as the employee does at the employee’s wage. The employer must consider the unemployed person qualified. This means that unemployment can certainly be eliminated if wages fall. At some point, either the employee decides to quit and just live off savings till social security kicks in or the unemployed person decides he or she doesn’t want the job. By definition, wage rigidity is needed to explain unemployment. This is true even if lower wages do not at all cause higher employment. If nothing else super low wages can convince people to leave the labor force eliminating unemployment that way. In this case wage flexibility doesn’t help the unemployed — it makes the alternative of working worse so they consider their horrible predicment the best they can hope for. I said it was twitty.
Second, things are unusual because we are in a liquidity trap. The reason nominal rigidities usually matter is that the real money supply could increase if the nominal money stock staid the same and wages and prices fell. From 1940 through 2008 this meant that wage and price flexibility should have prevented output from fallin. N ow, however, the money supply doesn’t matter since we are in a liquidity trap. In the IS-LM model (M/P) (money divided by the price level) appears. If P is free to adjust, then there can be no problem with insufficient aggregate demand. Therefore in all of the macro literature from 1940 through 2008, nominal rigidities were considered important. The idea here is wages go down so the firms cut prices (to maximize profits they would) so real balances (M/P) goes up so aggregate demand goes up so GDP goes up. There is no need for real wages to fall.
Right now this doesn’t matter as M/P doesn’t matter. But for decades and decades it mattered a lot, so nominal rigidities mattered. In practice, wages and prices are sticky so all reality based macroeconmists (“that’s not enough I need a majority” — Adlai Stevenson) agreed that nominal rigidities mattered. Now not so much. M/P doesn’t matter so P only matters because of debt deflation (lower P makes nominal mortgage debt an ever worse problem) so wage and price flexibility won’t save us so Keynesians don’t talk about it.
As always, don’t confuse “Keynesians” with Keynes. Keynes was not interested in nominal rigidities The General Theory through “The General Theory Restated” included nothing on nominal anything.