Measurement Alignment in Public–Private Partnership Evaluation: Sectoral Economic Evidence from Croatia

Public–private partnerships (PPPs) are implemented through individual contracts, but their performance is often judged with indicators observed at broader sectoral or national levels. This study develops a measurement alignment framework comprising intervention–measurement alignment, statistical visibility, attribution distance, outcome completeness, and comparison credibility and applies it to Croatian PPPs. The analysis combines the national PPP register with Eurostat data for 2000–2024. It uses a six-sector difference-in-differences benchmark, applies small-cluster inference and a 9999-draw Webb wild-cluster bootstrap, adds hours worked and national-accounts gross fixed capital formation, and evaluates timing, pandemic, contamination, spillover, intensity, and leave-one-out sensitivity. In the six-sector benchmark sample, the current-price GVA coefficient is 0.149 and statistically uncertain, whereas the real GVA coefficient is 0.256 and remains supported by the wild-cluster bootstrap (p = 0.009). In the 16-sector comparison sample, current-price and real GVA estimates remain positive but are estimated with wider uncertainty. Employment, hours worked, real productivity, and real investment show no robust broad effects, while event-study diagnostics reveal poorer pre-treatment comparability in the 16-sector comparison sample. The evidence supports a cautious positive output association, not a general causal growth claim, and demonstrates that PPP accountability requires indicators aligned with project mechanisms, geography, timing, and accounting visibility. The framework explicitly recognizes environmental performance as a required outcome domain, but the available sector-level data do not permit a direct estimate of PPP environmental impacts.