This paper investigates the effect of intra-generational mobility patterns on collective social action. We start with the assumption that employees tend to collective action in pursuing their economic interests only if their social position is homogeneous, stable in time and characterized by privileges (or structural disadvantages). We believe that patterns of intra-generational mobility (and not only those of inter-generational mobility) are crucial for these preconditions of collective action. These conditions can come into effect only in systems of 'closed positions', where intra-generational mobility is restricted. In systems of open positions, a high degree of intra-generational mobility prevents the existence of homogeneous, stable and privileged social positions. In addition, the institutional arrangements of a given society, especially the educational system, determine to a great extent whether occupational positions are closed or not. In societies with standardized, stratified and differentiated educational systems, intra-generational mobility is restricted by credentialist allocation regimes so that the three conditions are fulfilled and patterns of collective action have a high probability of arising. This hypothesis is tested by an international comparison of effects on perceived social inequality using data from the International Social Justice Project (1991, 1996). It turns out that, as expected, in credentialist countries, educational titles and class position have stronger effects on perceived social inequality than in non-credentialist societies. But it was found that the economic system also plays an important role in the structuring of perceived inequality.
