Liu, Luyang2026-02-222026-02-22https://hdl.handle.net/1885/733805761This thesis examines the detrimental effects of perceived age discrimination (PAD) on older workers' job performance. It begins with a comprehensive literature review on the antecedents and outcomes of PAD in the workplace and the underlying mechanisms and boundary conditions. Next, it presents the theoretical framework and hypotheses, which are grounded in conservation of resources theory. The proposed model suggests that PAD negatively influences older workers' job performance via reduced job engagement, with job level serving as a critical moderator. The model was tested on 1,442 Australian older workers, controlling for lagged variables at each stage. The results demonstrate that PAD in the workplace undermines older workers' task and proactive performance via reduced job engagement. Older workers with a lower job level (e.g., frontline employees) experience greater negative consequences from PAD compared with those with higher job levels (e.g., managers), resulting in lower job engagement, thus poorer task performance. However, the influence of PAD on the proactive performance of older workers does not differ across job levels. These findings underscore the need to protect older frontline workers, who experience stronger negative effects of PAD. This thesis contributes to conservation of resources theory and the PAD literature. First, it addresses why and how PAD undermines older workers' job performance and identifies those who are particularly vulnerable to these detrimental effects. Second, it offers a novel perspective by examining how job level functions as a "resource caravan" that can protect older workers against PAD, thereby advancing the resource perspective beyond its traditional focus on discrete resources at a given point in time. Third, it advances the research on the discrimination--performance relationship by examining job performance more comprehensively and providing a role-based perspective to better understand how PAD influences job performance. Finally, the thesis reconciles the mixed findings on the relationship between PAD and job engagement by bridging two research perspectives--the resource-based and the role-based perspectives. From the perspective of management practice, this thesis demonstrates that the adverse effects of PAD vary with job level, highlighting that there is no one-size-fits-all solution for supporting older workers and the importance of resources to mitigate age discrimination in the workplace. Finally, the thesis presents future research directions, such as replicating the model with broader samples across cultural contexts and clarifying the inconclusive role of job level in the relationship between PAD and proactive performance.en-AU202610.25911/251Q-FD10