These data contain a residential isolation value for non-Hispanic blacks (NHB) and non-Hispanic whites (NHW) at the census block group level. Population counts from the 1990 census using the 2010 census boundaries are used to calculate the index. For each block group, the index is the proportion of the population (NHB or NHW) in the index block group and block groups adjacent to the index block group. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent block groups.

Segregation is the physical separation of members of one racial, ethnic, social, or economic group from members of another group. This dataset measures the segregation of blacks from non-blacks. The segregation data come from decadal Census data spanning the years of 1890 to 2010. In addition to the segregation data, there is also supplemental city/metropolitan area data and the original ward and tract data that can be used to construct the indices. Segregation---Indices-of-Clustering--Concentration--and-Centralization: These indices require information on latitude and longitude of each census tract and are available only for 1990. Segregation---Indices-of-Dissimilarity-and-Isolation: Indices of dissimilarity and isolation. The "allseg" file includes all years 1890-1990. Supplemental-Data: The "allsup" file includes supplemental data for all years 1890-1990.

A statistical method called a dissimilarity index was used to quantify how segregated the region is among its census tracts, first by race and ethnicity, and then by income. The indices use decennial census tract data for years 1990 and 2000. The U.S. Census Bureau’s American Communities Survey (ACS) five-year period estimates. The Racial/Ethnic Segregation Index is an indicator of how segregated the region's census tracts are, relative to the regional distribution of white, non-Latinx population and people of color and Latinx populations. In a given year, values show dissimilarity in the racial and ethnic makeup of tracts across the region, and demonstrates the percentage of the population that would, theoretically, need to relocate in order to match the region's racial and ethnic makeup. The higher the index value, the higher the segregation is among white, non-Latinx and other races/ethnicities. The Income Segregation Index is an indicator of how segregated the region's census tracts are by income, relative to the regional distribution of low-income households. Low-income is defined as households below 200% of the federal poverty rate. This index shows dissimilarity in income for census tracts across the region for each year displayed, and demonstrates what percentage of the population would need to relocate to another census tract in order to match the income distribution for the entire region. The higher the index value, the greater the geographic concentration of wealth or poverty.

These data contain a residential isolation value for non-Hispanic blacks (NHB) and non-Hispanic whites (NHW) at the census block group level. Population counts from the 2000 census using the 2010 census boundaries are used to calculate the index. For each block group, the index is the proportion of the population (NHB or NHW) in the index block group and block groups adjacent to the index block group. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent block groups.

These data contain a residential isolation value for non-Hispanic blacks (NHB) and non-Hispanic whites (NHW) at the census tract level. Population counts from the 2013-2017 5-year American Community Survey (ACS) are used to calculate the index. For each block group, the index is the proportion of the population (NHB or NHW) in the index block group and block groups adjacent to the index block group. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent tracts.

These data contain a residential isolation value for people with or without a college degree at the census block group level. Population counts from the 2000 census are used to calculate the index. For each block group, the index is the proportion of the population (with or without a college degree) in the index block group and block groups adjacent to the index block group. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent block groups.

These data contain a residential isolation value for people with or without a college degree at the census block group level. Population counts from the 2013-2017 5-year American Community Survey (ACS) are used to calculate the index. For each block group, the index is the proportion of the population (with or without a college degree) in the index block group and block groups adjacent to the index block group. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent block groups.

In 2017, the California Tax Credit Allocation Committee (CTCAC) and the Department of Housing and Community Development (HCD) created the California Fair Housing Task Force (Task Force). The Task Force was asked to assist CTCAC and HCD in creating evidence-based approaches to increasing access to opportunity for families with children living in housing subsidized by the Low-Income Housing Tax Credit (LIHTC) program.

This feature set contains Resource Opportunity Areas (ROAs) that are the results of the Task Force's analysis for the two regions used for the San Francisco Bay Region; one is for the cities and towns (urban) and the other is for the rural areas. The reason for treating urban and rural areas as separate reasons is that using absolute thresholds for place-based opportunity could introduce comparisons between very different areas of the total region that make little sense from a policy perspective — in effect, holding a farming community to the same standard as a dense, urbanized neighborhood.

ROA analysis for urban areas is based on census tract data. Since tracts in rural areas of are approximately 37 times larger in land area than tracts in non-rural areas, tract-level data in rural areas may mask over variation in opportunity and resources within these tracts. Assessing opportunity at the census block group level in rural areas reduces this difference by 90 percent (each rural tract contains three block groups), and thus allows for finer-grained analysis.

In addition, more consistent standards can be useful for identifying areas of concern from a fair housing perspective — such as high-poverty and racially segregated areas. Assessing these factors based on intraregional comparison could mischaracterize areas in more affluent areas with relatively even and equitable development opportunity patterns as high-poverty, and could generate misleading results in areas with higher shares of objectively poor neighborhoods by holding them to a lower, intraregional standard.

To avoid either outcome, the Task Force used a hybrid approach for the CTCAC/HCD ROA analysis — accounting for regional differences in assessing opportunity for most places, while applying more rigid standards for high-poverty, racially segregated areas in all regions. In particular:

Filtering for High-Poverty, Racially Segregated Areas The CTCAC/HCD ROA filters areas that meet consistent standards for both poverty (30% of the population below the federal poverty line) and racial segregation (over-representation of people of color relative to the county) into a “High Segregation & Poverty” category. The share of each region that falls into the High Segregation & Poverty category varies from region to region.

Calculating Index Scores for Non-Filtered Areas The CTCAC/HCD ROAs process calculates regionally derived opportunity index scores for non-filtered tracts and rural block groups using twenty-one indicators (see Data Quality section of metadata for more information). These index scores make it possible to sort each non-filtered tract or rural block group into opportunity categories according to their rank within the urban or rural areas.

To allow CTCAC and HCD to incentivize equitable development patterns in each region to the same degree, the CTCAC/HCD analysis 20 percent of tracts or rural block groups in each urban or rural area, respectively, with the highest relative index scores to the "Highest Resource” designation and the next 20 percent to the “High Resource” designation.

The region's urban area thus ends up with 40 percent of its total tracts with reliable data as Highest or High Resource (or 40 percent of block groups in the rural area). The remaining non-filtered tracts or rural block groups are then evenly divided into “Low Resource” and “Moderate Resource” categories.

Excluding Tracts or Block Groups The analysis also excludes certain census areas from being categorized. To improve the accuracy of the mapping, tracts and rural block groups with the following characteristics are excluded from the application of the filter and from categorization based on index scores: ● Areas with unreliable data, as defined later in this document; ● Areas where prisoners make up at least 75 percent of the population; ● Areas with population density below 15 people per square mile and total population below 500; and ● Areas where at least half of the age 16+ population is employed by the armed forces, in order to exclude military base areas where it is not possible to develop non-military affordable housing.

Excluded tracts and rural block groups are identified as “nan” in the attribute table.

The full methodology used by the Task Force can be found in the California Fair Housing Task Force Opportunity Mapping Methodology report (https://www.treasurer.ca.gov/ctcac/opportunity/2022/2022-hcd-methodology.pdf) on the California Office of State Treasurer website.

Source data and maps can be found on the CTCAC/HCD Opportunity Area Maps page (https://www.treasurer.ca.gov/ctcac/opportunity.asp).

Diagnoses of HIV infection, linkage to HIV medical care within 1 month, and viral suppression within 6 months of HIV diagnosis among adults aged ≥18 years, by Index of Concentration at the Extremes (ICE)—United States and Puerto Rico (census tract levela), 2019.

HIV testing among adults aged ≥18 years, by Index of Concentration at the Extremes (ICE), 2019—county levela, United States and Puerto Rico.

These data contain a residential isolation value for people with or without a college degree at the census tract level. Population counts from the 2013-2017 5-year American Community Survey are used to calculate the index. For each tract, the index is the proportion of the population (with or without a college degree) in the index tract and tracts adjacent to the index tract. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent block groups. Islands (areal units with no first-level adjacent areal units) are removed as it is not possible to calculate isolation for units with no adjacent tracts.