Household Waste-Sorting Dataset from Hai Phong, Vietnam

This dataset supports the development and validation of the Environmental Culture Index (ECI) presented in the study “Developing an Environmental Culture Index for Household Waste Sorting”. It contains 445 complete, de-identified responses collected through a household waste-sorting survey in Hai Phong, Vietnam, from July to August 2025. The analytical dataset contains 74 positively oriented five-point Likert-scale items mapped to 15 fixed first-order constructs across Knowledge (K), Action (A), Utility (U), and Contribution (C). The synchronized repository includes Supplementary Files S1-S7, the Vietnamese questionnaire and corrected US-English analytical translation, supplementary results and figures, the complete three-phase code-and-results archive, and integrity records. The locked workflow evaluates 22,785 theory-admissible KAUC specifications and identifies KAUC_K00011_A011_U1000_C011 as the final reference specification (35 items, seven constructs), with tau = 2.9 and gamma = 2.0. Direct personal identifiers and timestamps have been removed. The ECI is a domain-specific diagnostic for household waste sorting, not a national-culture score or causal estimate of recycling performance.