Risk Cost Measurement of Value for Money Evaluation Based on Case-Based Reasoning and Ontology: A Case Study of the Urban Rail Transit Public-Private Partnership Projects in China

Risk is demonstrated as one of the most crucial drivers value for money (VFM) in public–private partnerships (PPP), but previous studies, risk cost estimation quantitative evaluation VFM was still a dilemma that strongly depended on specialist discretion or had low methodological operability. This paper establishes prediction model estimating phase through combination case-based reasoning (CBR) and ontology technology. PPP information established to provide technical basis knowledge representation CBR cycle. Then, according whether data were qualitative, similarity calculation methods used retrieval similar cases. The conceptual semantic algorithm based tree structure well implemented compare abstract information. After cases extracted, revision mechanism followed when there deviations Finally, costs target case obtained by weighting extracted similarity. An empirical analysis performed with 18 historical projects from China Public–Private Partnerships Center. results showed relative errors between estimated actual total retained 11.05% 2.41%, respectively. indicates could achieve better small errors, which validates availability model. Based proposed model, this research an extensible It promotes integration interoperability domain, can be further expanded requirements. Coherent accuracy provided whole CBR-based measurement process, has offered systematic objective method projects.