An inverted-U relationship between product market competition and growth in an extended Romerian model

The influence of product market competition on growth is reconsidered by developing an extension of the basic Romerian model of horizontal product innovation. We find that the relationship between competition and growth is inverse-U shaped, provided that the non accumulated factor input (e.g. labour) is employed in each economic activity. We explain this result by the interplay between two effects. For low values of product market competition, the positive resource allocation effect (the effect that an increase of competition has on the sectoral distribution of labour) outweigh s the negative profit incentive effect (the effect that an increase of competition has on firms' incentive to innovate). When prod uct market competition is intense, the resource allocation and pr ofit incentive effects are both negative and reinforce each other in inducing a negative correlation between competition and growth