important in explaining welfare losses from revenue productivity dispersion …

productivity across firms within narrowly defined sectors. Our hypothesis is that periods of rapid innovation are accompanied by … high rates of entry, significant experimentation and, in turn, a high degree of productivity dispersion. Following this … experimentation phase, successful innovators and adopters grow while unsuccessful innovators contract and exit yielding productivity …

firms and reductions in earnings per worker. Productivity gains arise mainly from an accelerated exit of less productive …