Investigating standardized criteria to evaluate the impact of agro-healing programs on psychological and interpersonal outcomes: Utilizing normalization methods

Nature- and agriculture-based activities are increasingly used as accessible, non-pharmacological supports for psychological well-being, yet heterogeneous designs and measures complicate interpretation across studies. To provide practice-oriented benchmarks, we estimate reference values for key psychological outcomes using nonparametric bootstrap resampling. We systematically screened recent studies, harmonized outcome directions and units, and computed bootstrap-based reference values with percentile intervals. When appropriate, parametric tests were complemented by robust and nonparametric summaries, and findings were verified via sensitivity analyses. Across eligible studies, participants receiving nature/agriculture programs showed improvements in affect, stress/anxiety, self-esteem, and self-efficacy. Benchmarks derived from bootstrap distributions offer interpretable ranges for expected change, aiding judgments of practical significance across diverse settings. The bootstrap-based benchmarks provide a transparent, reproducible reference for planning, delivering, and evaluating nature- and agriculture-based programs. Practically, they support goal-setting, progress monitoring, and evidence-informed decisions in clinical, community, and educational contexts. Academically, they enhance cross-study comparability, enable cumulative synthesis, and offer a stable basis for theory-driven hypotheses about mechanisms and program design. We estimate benchmark/reference values for key psychological outcomes using nonparametric bootstrap resampling. The resulting benchmarks provide interpretable ranges for expected change and can inform goal-setting, progress monitoring, and evidence-informed decisions across clinical, community, and educational settings.