BACKGROUND: To achieve fair-coverage decision making, both material criteria and criteria of procedural justice have been proposed. The relationship between these is still unclear. OBJECTIVE: To analyze hypotheses underlying the assumption that more assessment, transparency, and participation have a positive impact on the reasonableness of coverage decisions. METHODS: We developed a structural equation model in which the process components were considered latent constructs and operationalized by a set of observable indicators. The dependent variable "reasonableness" was defined by the relevance of clinical, economic, and other ethical criteria in technology appraisal (as opposed to appraisal based on stakeholder lobbying). We conducted an Internet survey among conference participants familiar with coverage decisions of third-party payers in industrialized countries between 2006 and 2011. Partial least squares path modeling (PLS-PM) was used, which allows analyzing small sample sizes without distributional assumptions. Data on 97 coverage decisions from 15 countries and 40 experts were used for model estimation. RESULTS: Stakeholder participation (regression coefficient [RC] =0.289; P = 0.005) and scientific rigor of assessment (RC = 0.485; P < 0.001) had a significant influence on the construct of reasonableness. The path from transparency to reasonableness was not significant (RC = 0.289; P = 0.358). For the reasonableness construct, a considerable share of the variance was explained (R (2) = 0.44). Biases from missing data and nesting effects were assessed through sensitivity analyses. Limitations. The results are limited by a small sample size and the overrepresentation of some decision makers. CONCLUSIONS: Rigorous assessment and intense stakeholder participation appeared effective in promoting reasonable decision making, whereas the influence of transparency was not significant. A sound evidence base seems most important as the degree of scientific rigor of assessment had the strongest effect.