How do within-person changes due to aging affect job performance?

•This article addresses the relationship between age and job performance.•First, it highlights five major within-person changes related to aging.•Next, it discusses how these within-person changes affect job performance.•The cumulative evidence suggests that older workers are still productive workers.

As the mean age of the workforce in industrialized countries trends upward, increasing attention has been paid to group-level differences between younger and older workers in terms of job performance. The present article takes an alternative perspective by examining within-person changes that occur with aging and how the process of aging affects employees' workplace behavior. We begin by highlighting five areas in which we observe major within-person changes related to aging: (1) cognitive capacity, (2) personality, (3) goal orientation, (4) social-emotional experience, and (5) health. Then, we demonstrate why and how these within-person changes due to aging affect core task performance, citizenship behavior, and counterproductive work behavior across the lifespan.