According to my current understanding, the California 'builder's remedy' policy has opened up a much more permissive permitting regime for residential buildings in many cities, as a result of the state finding those cities' ordinary rules to be out of compliance with state law.
This market asks how many housing units (i.e., homes or apartments) will be:
(i) issued their major zoning/permitting approvals in 2022 or 2023 (i.e., those approvals that one would reasonably expect to be most difficult to secure)...
(ii) ...and likely would not have gotten those approvals without the availability of the builder's remedy...
(iii) ...and are actually built and fitted out for occupancy (though not necessarily occupied or given final approval for occupancy) by the end of 2024.
I'll attempt to estimate the effect of the builder's remedy at the granularity of housing units to the extent possible. If a 150-unit apartment building is constructed on a site where a 40-unit building would have been legal under the preexisting zoning/permitting rules, I'll count that as 110 (=150-40) units for the purpose of this total.
This will be difficult to resolve precisely, and I don't currently plan to do any project-by-project or city-by-city research to estimate the number myself. This will be answered according to my best guess based on publicly available reports readable by non-experts. I'll happily discuss any sources that commenters suggest I use.