The interactive (moderating) effects of public service motivation: a systematic review

Research on public service motivation (PSM) has increasingly emphasised its interactive (moderating) effects, yet this literature remains theoretically fragmented. This systematic review synthesises evidence from 153 empirical studies published between 2001 and 2024 to clarify how and when PSM shapes work outcomes through interaction with other factors. This article identifies five recurring themes underlying PSM’s interactive effects: person – environment fit, PSM as a personal resource, expectancy sensitivity, saturation, and motivation crowding-out and crowding-in. Two of these themes are under-theorised. The expectancy sensitivity effect shows that high-PSM individuals may react more strongly to work and non-work conditions due to their elevated expectations, whereas the saturation effect indicates diminishing marginal returns of contextual enhancements on performance outcomes among already highly motivated individuals. Overall, these five themes clarify how the influence of PSM is contingent on other factors and how PSM itself functions as a moderator. This review advances theoretical understanding of PSM’s interactive effects and charts an agenda for future research.