This paper introduces a new way to measure competition based on firms' profits. Within a general model, we derive conditions under which this measure is monotone in competition, where competition can be intensified both through a fall in entry barriers and through more aggressive interaction between players. The measure is shown to be more robust theoretically than the price cost margin. This allows for an empirical test of the problems associated with the price cost margin as a measure of competition.JEL codes: D43, L13

This paper derives new results on the welfare effects of employment protection. Using data from 17 OECD countries, we show that there exists an inverse U-shape relationship between employment protection and economic growth. Using a simple theoretical model with non-contractible specific investments, we show that over some range increasing employment protection does indeed raise welfare. We also show that the optimal level of employment protection depends on other labour market features, such as the bargaining power of workers and the existence of wage rigidities like the minimum wage. Copyright (c) The London School of Economics and Political Science 2007.

I analyze the effects of competitive pressure on a firm's incentives to invest in product and process innovations. I present a framework incorporating the selection and adaption effects of product market competition on efficiency and the Schumpeterian argument for monopoly power. The effects of competition on a firm's innovations depend on whether a firm is complacent, eager, struggling, or faint, which is determined by the firm's efficiency level relative to that of its opponents. Finally, the following tradeoff is pointed out: a rise in competitive pressure cannot raise both product and process innovations at the industry level.