The Future of Work: Why Wages Aren’t Keeping Up: ... The suggestion I want to make is that one important reason for the failure of real wages to keep up with productivity is that the division of rent in industry has been shifting against the labor side for several decades. This is a hard hypothesis to test in the absence of direct measurement. But the decay of unions and collective bargaining, the explicit hardening of business attitudes, the popularity of right-to-work laws, and the fact that the wage lag seems to have begun at about the same time as the Reagan presidency all point in the same direction: the share of wages in national value added may have fallen because the social bargaining power of labor has diminished. This is not to say that international competition and the biased nature of new technology have no role to play, only that they are not the whole story. Internal social change and the division of rent matter too.
Now I would like to connect this hypothesis with another change taking place in the labor market. Lacking anything more euphonious, I will call it the casualization of labor. The proportion of part-time workers has been rising: both those who prefer it that way and those who would rather have a full-time job. So is the number of temporary workers... So are the numbers of workers on fixed-term contracts and independent contractors, many of whom are doing the same work as they once did as regular employees. These are all good-faith members of the labor force; they are employed but without what used to be thought of as a regular job.
This shift toward more casual labor interacts with the issue of the division of rents. Casual workers have little or no effective claim to the rent component of any firm’s value added. They have little identification with the firm, and they have correspondingly little bargaining power. Unions find them difficult to organize, for obvious reasons. If the division of corporate rents has indeed been shifting against labor, an increasingly casual work force will find it very hard to reverse that trend.