HMFITS-IDM: an episode-level decision model for interacting constraints, informed by four Japanese earthquake responses

Introduction Operational decisions during disasters require more than a list of scarce resources: decision-makers must also assess which actions remain feasible. This paper proposes the Human, Material, Financial, Information, Time, and Safety/Quality-Integrated Decision Model (HMFITS-IDM) to support this assessment. Methods The framework was specified through a conceptual, abductive approach and applied to eight decision reconstructions from four Japanese earthquake responses; the reconstructions draw on 14 academic and official sources. The procedure separates the decision frame from resource and feasibility appraisal, examines dependencies among actionable restrictions, compares candidate constraint sets against a fixed decision problem, and links the result to action and reappraisal. Each judgment is tied to a source location, and reported facts are distinguished from analytical judgments and proposed responses. Results The Kumamoto example traces the reasoning from exhausted local receiving capacity, incomplete destination information, prolonged outdoor waiting, and patient-care requirements to a confirmed receiving arrangement and differentiated transport. Material is retained in the candidate explanation, but because smaller representations remain viable, minimality cannot be established. In other reconstructions, resource availability is distinguished from missing evidence, and one narrow transport-disruption decision can be explained by a single restriction. The Noto evidence also documents how financial uncertainty affected requests for support. Overall, the reconstructions support decision-specific explanations rather than a dominant bundle recurring within each earthquake pair. Discussion HMFITS-IDM offers a procedure for making the basis of operational choices explicit and testing whether a smaller constraint explanation is sufficient. It accommodates competing and unresolved interpretations without requiring a bundle for every decision. In practice, the worksheet records why an option is restricted, what change could restore it, and when the decision should be reappraised. Reliability across independent coders, comparative utility, and prospective effectiveness remain to be evaluated.