What do y'all think of George Selgin's brand of NGDP targetting, as outlined in his work Less Than Zero? He argues that NGDP targetting should follow a productivity norm, allowing changes in total factor productivity to decrease (or increase) the price level. In other words, let aggregate supply do what it will to the price level; keep aggregate demand on an even keel. He says this would reduce the distortionary effects of monetary policy across industries, since some prices industries may experience idiosyncratic productivity shocks that affect the whole price level.