The connection between class and voting choices has been the subject of controversy in recent years. At one time, most scholars regarded class as the primary basis of political alignments in industrial societies, at least in those not sharply divided by religion or ethnicity. In the 1970s, however, researchers in several countries argued that the connection between class and party was now weakening. Several researchers hold that the political significance of class increases in the early stages of industrialization, but declines in advanced industrial societies. Thus, the leading position of social class was characteristic of a particular stage of society that is now passing. Although this view is widely accepted, it has attracted a number of critics, some argue that political alignments have not actually changed very much in recent years, while others stress the diversity of national experiences. A major reason for the continued disagreement is simply the scarcity of evidence. To measure the association between class and party choice precisely, one must have individual-level data, which are not available for most countries until the 1970s.