Why universal design fails: a Convergent Appreciation / Divergent Activation (CADA) model for culturally diverse cities

Urban leftover spaces represent significant potential, yet universal design (UD) approaches often struggle to meet the needs of diverse multicultural contexts. Through constructivist grounded theory analysis of a participatory design charrette with 12 culturally diverse participants in Wellington, New Zealand, this study proposes the Convergent Appreciation/Divergent Activation (CADA) model. While all participants agreed that spatial problems such as safety, neglect and underutilized space potential were present (94–100% agreement in problem agreement) their solutions diverged radically along five emergent orientations: Systems-Harmony (n = 3), Efficiency-Quantification (n = 2), Social-Collective (n = 3), Place-Stewardship (n = 2) and Practical-Utilitarian (n = 2). A bootstrap resampling procedure (10,000 iterations) was used as a descriptive robustness check on orientation consistency, yielding 95% confidence intervals spanning 0.87 to 1.00. Participants’ design choices showed high orientation consistency (81–94%), indicating non-random alignment with the five orientations. The CADA model demonstrates that inconsistent solution logics in multicultural urban development present challenges to uniform evaluation. Given the confounding role of professional training in isolating cultural variables, this research frames itself as exploratory theory building rather than hypothesis testing. A provisional pluralistic design framework is proposed to structure how multiple spatial logic systems might be integrated in future validation studies.