Schedule overruns in public road infrastructure impose significant costs in developing economies, yet how public investment management (PIM) governance shapes project schedules remains underspecified. This study proposes and tests a mediation specification in which strategic planning alignment (SPA) transmits the effects of upstream PIM management constructs on schedule performance in Vietnamese public road infrastructure.
A sequential mixed-methods design was employed. The Fuzzy Delphi Method (FDM) was applied with an expert panel to validate a 16-indicator measurement instrument across four constructs: SPA, organisational capacity and implementation (OCI), monitoring, control and audit (MCA) and inter-agency coordination (IAC). Partial least squares structural equation modelling (PLS-SEM) was then applied to survey data from 179 Ministry of Construction professionals to test the hypothesised mediation model.
Full mediation is confirmed. No upstream construct – OCI, MCA or IAC – exerts a statistically significant direct effect on schedule performance; all effects are transmitted through SPA. OCI exerts the largest indirect influence, followed by MCA and IAC, with SPA as the sole significant direct predictor of schedule performance.
This study provides the first structural equation-based evidence that investment plan quality functions as the necessary intermediary between institutional governance capacity and infrastructure project delivery outcomes. The findings directly challenge the co-equality assumption embedded in landmark PIM frameworks, including the World Bank's PIM Diagnostic and the IMF's PIMA, and offer a validated diagnostic instrument for project-level PIM assessment in developing-country contexts.
