Problem, research strategy, and findings: Several U.S. states with high housing costs have recently adopted laws intended to promote infill development. These new laws expand state agencies’ supervisory responsibilities to ensure that local governments comply with state mandates. Effective administration of these laws will require state agencies to accurately estimate the amount of new housing that might be created and to target review to the jurisdictions that are failing to meet the relevant requirements. Here we present quantitative tools both for prioritizing review of local plans and zoning ordinances and for estimating future housing development. We applied the tools to the implementation of California laws requiring local governments to amend their zoning ordinances to allow accessory dwelling units on parcels zoned for detached single-family housing development. We provide computer code, written in the open-source statistical computing language R, that implements these tools. Although we present off-the-shelf tools, our proposed tools should supplement other regulatory techniques rather than serving as a substitute. Takeaway for practice: Requirements for local governments to allow infill development should be accompanied by mandates for data collection. With good data, state agencies can use open-source statistical software to create quantitative measures that can help estimate future housing production and set priorities for reviewing local plans and zoning ordinances.

City councils are on the front lines of California’s housing crisis. But local lawmakers who understand that California needs to accommodate a lot more housing are stuck in a political bind. Wherever they might put new housing, neighborhood groups spring up and oppose it. The same groups will have money to spend or voters to turn out at the next election. What’s a well-meaning city councilperson to do? Our answer: California’s “housing element” process provides a way forward. California requires cities to periodically adopt a state-approved plan, called a housing element, which accommodates the city’s share of regional housing need. These plans are reviewed and certified for compliance by the state Department of Housing and Community Development (HCD). Cities across the state will adopt new housing elements between 2020 and 2022, guiding development for the next eight years. This process hasn’t always worked well in the past, but the legislature and HCD have recently strengthened the framework. There are now substantial political advantages for city officials to pursue pro-housing policies through their housing element, rather than through the normal municipal lawmaking channels.

This report evaluates California’s official housing target for the San Francisco Bay Area. While the Bay Area received a substantially larger target for the upcoming planning cycle than it had in the previous cycle, the relative increase in the Bay Area target was a lot smaller than that for the state’s other major metropolitan region, Los Angeles, which forms part of the Southern California Association of Governments. We argue that the Bay Area’s lower target reflects, in part, the state’s failure to account for the fact that the Bay Area leads the nation in supercommuters, many of whom work in the Bay Area but have been driven by the region’s housing shortage to live outside of it. State law requires an adjustment for regional “jobs-housing imbalance,” yet none was made. The Bay Area target was also deflated by the Association of Bay Area Governments’ choice of “comparator regions,” a choice which presupposed that the Bay Area should be benchmarked against similarly housing-supply-constrained regions; and by the state’s decision not to fully account for the needs of presently cost-burdened households. Altogether, we estimate that the announced target of 441,000 new housing units was at least 245,000 units short of the mark.