lished skills, given that younger workers move out of jobs much more frequently than older ones (Swaen et al., 2002). It is also possible that typical jobs do not demand continuous maximal performance to the same extent as laboratory-devised tasks. Older workers may find ways to accommodate to changes in capabilities that enable them to continue performing at satisfactory levels. An example would be the adoption of reading glasses to enable them to compensate for normative development of presbyopia (inability to focus on near objects). However, future findings about the relation of age to performance may change to the extent that the demand for new, nonpracticed abilities increases in the workplace. If current trends toward later retirement strengthen, and if there is increased job mobility, we may expect to see some narrowing in the gap between lab and life findings.
An important limitation on the conclusions about age and productivity is the insensitive measures of productivity. For example, in psychological literature productivity is often defined in terms of simple output. In economic analyses, a firm that produces the same number of goods and services using fewer inputs than a competitor is considered more productive. As a group, older workers are usually paid more than younger workers. Examined cross-sectionally, income tends to peak in the late 40s and early 50s compared with earlier and later ages (U.S. Bureau of the Census, 2002). Even if they show equivalent product output, older workers would be more costly to employ (or less cost-effective) by virtue of their higher salaries (and possibly by the higher cost of their benefits). But, cross-sectional analyses neglect the issues pertaining to lifetime costs and benefits to a firm and to a worker for an employment contract. Current higher wages paid to older workers may be explicable by delayed payment contract models (e.g., Hutchens, 1986). Such models argue that single-period accounting of the relative costs of labor do not fully capture the lifetime nature of labor contracts and the value of workers to their firms over their complete tenure.
So there is mixed news on the productivity question. Older workers appear to be as capable (or incapable) as younger ones in performing their jobs. However, older workers may appear to be less efficient than younger ones. Hence, there would appear to be a strong incentive to provide training and retraining to increase job productivity and efficiency. Or there may be an incentive to replace costly but equally productive (for output) older workers with younger, less expensive ones, should replacement prove less expensive than investing in training.
An important prerequisite for productivity is being available for work. Absenteeism, differentiated into voluntary (e.g., calling in sick when not sick) and involuntary (true illness or disorder or injury) types, does show age-related differences. Martocchio’s (1989) metanalysis used frequency of absence to index voluntary absenteeism and time loss to index involuntary