Starting from the theoretical argument underlying the "hump shape" hypothesis, the paper investigates the various dimensions of centralisation in the wage formation process. The diversity of effects discussed in the paper makes it harder to arrive at unambiguous policy conclusions. Careful analysis of the various features and economy-wide direct as well as indirect effect of the degree of centralisation in the wage formation process suggests that there exists various trade-offs, the most important of which appears to be that between real wage restraint and relative wage flexibility: centralisation favours the former but reduces the latter. This suggests that its effect on macroeconomic performance depends on the type of shocks affecting the economy ...