ABAG-MTC staff developed this tool to support the Housing Methodology Committee (HMC) as they developed an initial recommendation for a Regional Housing Needs Allocation (RHNA) methodology. This tool was intended to help the HMC and members of the public explore the impact of different methodology factors and income allocation approaches discussed during HMC meetings.
On September 18, 2020, the HMC voted to recommend a RHNA methodology that uses the Bottom-Up income allocation approach, Future Year 2050 Households from the Plan Bay Area 2050 Blueprint for the methodology's baseline, and the following factors and weights:
Very Low and Low Units |
Moderate and Above Moderate Units |
70% Access to High Opportunity Areas 15% Job Proximity – Auto 15% Job Proximity – Transit |
40% Access to High Opportunity Areas 60% Job Proximity – Auto |
On October 1, 2020, the ABAG Regional Planning Committee voted to recommend this methodology for approval by the Executive Board, and the Board approved its release as the Proposed RHNA Methodology for public comment on October 15, 2020. As required by law, ABAG held a public comment period from October 25 to November 27.
ABAG’s Draft RHNA Methodology is similar to the Proposed Methodology with two notable differences. First, it incorporated 2050 Households projections from the Plan Bay Area 2050 Final Blueprint, the San Francisco Bay Area’s regional plan slated for adoption later this year. Second, in response to public comments, it integrated the “equity adjustment” that was originally proposed by several HMC members. The Draft RHNA Methodology and Final Blueprint were adopted by the ABAG Executive Board on January 21, 2021, with the Metropolitan Transportation Commission adopting the Final Blueprint on January 27, 2021. Accordingly, the baseline options in this tool based on Plan Bay Area 2050 have been updated with data from the Final Blueprint. For more information about the equity adjustment and the RHNA methodology adopted by the Executive Board, see this document.
Although the HMC has completed its work and ABAG has adopted a Draft RHNA Methodology, ABAG-MTC staff is leaving this tool online to help facilitate a better understanding of the RHNA methodology development process. However, the RHNA visualization tool does not include the equity adjustment, and so this tool cannot entirely replicate the methodology adopted by ABAG. Visit the RHNA home page for more information about the next steps in the RHNA process.
Note: there may be slight differences in the illustrative allocations produced by the online tool compared to those in previous official documents produced by ABAG staff due to rounding differences.
In contrast to the Income Shift, the Bottom-Up income allocation approach does not start with a total allocation assigned with a factor-based methodology. Instead, this approach builds up the total allocation by using factors to determine allocations for the four income categories separately. Factors are selected for the lower two income categories, and then for the upper two income categories, and a jurisdiction’s allocation within each income category is determined based on how the jurisdiction scores relative to the rest of the region on the selected factors. The jurisdiction’s total allocation is calculated by summing the results for each income category.
In this approach, the total number of units allocated to a jurisdiction is identified first using a weighted factor-based methodology, where weights determine the share of the Regional Housing Needs Determination (RHND) to be distributed according to each factor, and the “income shift” is then used to distribute a jurisdiction’s units among the four RHNA income categories. The Income Shift methodology compares a jurisdiction’s distribution of households by income to the distribution for the region. A jurisdiction that has a higher percentage of existing households in a given income category compared to the region receives a smaller share of units in that income category, and vice versa.