A Planetizen article on actions taken by municipalities opposed to Senate Bill 9, the California law allowing property owners to build additional units on lots zoned for single-family housing, cited research by Michael Storper, distinguished professor of urban planning at UCLA Luskin. Four Southern California cities have filed suit against the state, arguing that permitting the subdivision of single-family lots violates the California Constitution by taking away the rights of charter cities to have control over local land-use decisions. Storper issued a declaration in support of the plaintiffs that included a copy of a journal article he co-authored in 2019 that challenged the theoretical underpinnings that led to SB 9, which is intended to provide affordable housing options for Californians. “Blanket changes in zoning are unlikely to increase domestic migration or to improve affordability for lower-income households in prosperous areas,” the authors wrote. “They would, however, increase gentrification within metropolitan areas and would not appreciably decrease income inequality.”