Scope and process interdependencies: project portfolio management maturity

Purpose This study examines how inter-project interdependencies influence portfolio-level performance. Drawing on information processing theory (IPT), it distinguishes between scope interdependency (strategic alignment of deliverables) and process interdependency (executional and temporal linkages), and examines the moderating role of project portfolio management (PPM) maturity. Design/methodology/approach Survey data from 219 project professionals in South Korea were analysed using structural equation modelling to test the effects of interdependencies on average project fulfilment and average economic project success, with multi-group analysis assessing moderation by PPM maturity. Findings The results show that scope interdependency positively affects average project fulfilment, indicating benefits from strategic alignment across projects. In contrast, process interdependency has a negative effect, suggesting increased coordination and information-processing burdens during execution. Furthermore, higher levels of PPM maturity mitigate the negative impact of process interdependency and strengthen the relationship between average project fulfilment and average economic project success. Originality/value This study advances PPM research by conceptually and empirically distinguishing strategic (scope) and executional (process) interdependencies and demonstrating their opposing effects on portfolio-level performance. By integrating IPT with PPM maturity as a contingent information-processing capability, the study provides novel insights into how organisations can better manage complex inter-project relationships to enhance portfolio outcomes.