This paper investigates if significant differences exist between online and paper & pencil participants in a quarterly business survey in the German business?related services sector when respondents may freely choose to respond either online or by more conventional methods. It also analyzes the...

Theory predicts a positive relationship between market concentration and profitability in most scenarios. In empirical work, however, this relation is frequently not found or only a weak connection is observed. We compare the performance of concentration and market share variables, which are...