Market Growth and Industry Concentration
The thesis that industry growth tends to reduce the level of sellers' concentration is reviewed and empirically tested. The Nelson-Shepherd et al. conclusion that market growth reduced concentration between 1947 and 1958 does not receive positive support utilizing the most recent data covering 1947 to 1963. These recent data are in some respects superior to and in other respects inferior to those available in the past. Both simple and multivariate statistical techniques were used to test the main hypothesis as well as several supporting theses. For instance the evidence suggests that, reversing the causality, the initial level of concentration has no significant influence on an industry s subsequent growth rate.