Reliability and validity of the Vulnerability Index-Service Prioritization Decision Assistance Tool (VI-SPDAT) in real-world implementation

ABSTRACT This study examined the reliability and validity of the Vulnerability Index-Service Prioritization Decision Assistance Tool (VI-SPDAT), a widely-used assessment of the health and social vulnerabilities and housing needs of individuals experiencing homelessness. Homeless Management Information System data were obtained for 1495 individuals who were administered the VI-SPDAT between 2014 and 2016. Subsamples were selected for reliability and validity assessments. Results suggest there are challenges to the reliability and validity of the VI-SPDAT in practical use. VI-SPDAT total scores did not significantly predict risk of return to homeless services, while type of housing was a significant predictor. Vulnerability assessment instruments have important implications for communities working to end homelessness by facilitating prioritization of scarce housing resources. Findings suggest that further testing and development of the VI-SPDAT is necessary.