The wave of electoral volatility which swept across most of the West European polities in the late 1960s and 1970s has led many scholars to suggest that the European party systems are now experiencing a major transformation. Given such an emphasis in the contemporary literature, this article attempts to identify some of the key problems in defining what is meant by party system change. Four such problems are identified. First, that of distinguishing party change, on the one hand, and party system change, on the other. Second, the problem of treating measures of electoral volatility as indicators of cleavage decline, and the extent to which evidence of electoral change can be seen as a valid challenge to the Lipset-Rokkan `freezing' hypothesis. Third, the problem of determining the level of electoral volatility which actually `matters' in discussions of party system change. Fourth, the problem of the electoral bias itself, which often leads researchers to neglect other, non-electoral, dimensions of change which, in turn, may well prove to have been both more fundamental and more enduring.
