Oops? Interdisciplinary Stories of Sociotechnical Error| Quantifying Housing Need in California: The Erroneous Practice of Evidence-Based Policy

This article examines the breakdown of evidence-based policy schemes that assume the neutrality of its measurements through the case of California’s Regional Housing Need Assessment (RHNA). RHNA is an intergovernmental land use planning process that compels municipalities to demonstrate sufficient land capacity for their share of regional housing need. A 2018 state bill that reformed the codified methodology to measure housing need established a norm of fulfilled need based on a given California region’s deviation from a “comparable” or “healthy” housing market. I examine how the planning apparatus operationalized the comparable region standard by analyzing memos from regional governments that document data analyses and rationales. Critically analyzing the implementation of the methodology illustrates that the quantification of housing need is not a neutral and objective measure, but rather a sociotechnical project that reflects the institutional, political, and technical constraints of its context.