The Cost of Living Index as a Primary Driver of Homelessness in the United States: A Cross-State Analysis

Background: Homelessness persists as a critical global issue despite myriad interventions. This study analyzed state-level differences in homelessness rates across the United States to identify influential societal factors to help guide resource prioritization. Methods: Homelessness rates for 50 states and Washington, DC, were compared using the most recent data from 2020 to 2023. Twenty-five variables representing potential socioeconomic and health contributors were examined. The correlation between these variables and the homelessness rate was calculated. Decision trees and regression models were also utilized to identify the most significant factors contributing to homelessness. Results: Homelessness rates were strongly correlated with the cost of living index (COLI), housing costs, transportation costs, grocery costs, and the cigarette excise tax rate (all: P < 0.001). An inverse relationship was observed between opioid prescription rates and homelessness, with increased opioid prescribing associated with decreased homelessness (P < 0.001). Due to collinearity, the combined cost of living index was used for modeling instead of its individual components. Decision tree and regression models identified the cost of living index as the strongest contributor to homelessness, with unemployment, taxes, binge drinking rates, and opioid prescription rates emerging as important factors. Conclusion: This state-level analysis revealed the cost of living index as the primary driver of homelessness rates. Unemployment, poverty, and binge drinking were also contributing factors. An unexpected negative correlation was found between opioid prescription rates and homelessness. These findings can help guide resource allocation to address homelessness through targeted interventions.