How State Governments Shape Local Hazard Mitigation: A Text-Based Policy Similarity Approach

• In Event: Proactive Responses and Historical Accounts of Disasters

Abstract

This study examines how state-level hazard mitigation policies influence local planning in Ohio through a text-based policy similarity analysis. The Disaster Mitigation Act of 2000 requires local governments to develop FEMA-approved Local Hazard Mitigation Plans (LHMPs) to secure federal funding. However, the extent to which these local plans align with the State Hazard Mitigation Plan (SHMP) – reflecting top-down policy diffusion – remains unclear. We address this gap by measuring the textual alignment between Ohio’s SHMP and county LHMPs, shedding light on state-to-local policy convergence.

We adopt a mixed-methods approach that blends machine learning and statistical modeling to evaluate policy alignment. Using Word2Vec, we quantify the semantic similarity between mitigation goals in Ohio’s SHMP and those in 231 county LHMPs (2003–2021). We then employ beta regression to examine how goal type (action-oriented vs. hazard-specific) and plan authorship (government-authored vs. consultant-authored) relate to the degree of alignment. Additionally, Latent Dirichlet Allocation (LDA) topic modeling is applied to identify and trace the evolution of thematic priorities in local plans over time.

Our findings demonstrate a high degree of alignment between state and local mitigation goals, indicating a strong top-down influence. LHMPs with action-oriented goals exhibit significantly greater textual similarity to the SHMP than those focused on specific hazards, suggesting that state frameworks may implicitly encourage actionable strategies. The authorship of the plan also plays a role: locally authored plans tend to align more closely with state strategies, whereas plans prepared by private consultants show lower similarity. These patterns highlight how both the nature of goals and the planning process shape policy convergence.

The topic modeling results further reveal that Ohio’s local mitigation planning priorities have shifted significantly over the past two decades. We observe a transition from reactive, hazard-specific plans toward more proactive, community-engaged, and comprehensive approaches to disaster risk reduction in recent LHMPs. This evolution aligns with broader state priorities and emerging challenges, underscoring the influential role of state guidance in local policy development. Overall, the study contributes to policy diffusion and intergovernmental relations literature by demonstrating the significant impact of state frameworks on local plan content. It also offers practical insights for policymakers, suggesting that strengthened state guidance and support can enhance the coherence and effectiveness of local hazard mitigation plans.

Author

• Ruixiang Xie, Huazhong University of Science and Technology
  Presenting Author