Healthy Development Measurement Toolkit

Indicator HH.2.a Change in SF income relative to regional change in income

Data Source

U.S. Census 1999 and 2000, Geolytics software. Census variables used: 'Median household income last year - 1990' (MDHHY9); 'Median household income last year - 2000' (MDHHY0); 'Total occupied housing units - 2000' (OCCHU0); 'Total occupied housing units - 1990' (OCCHU9).

Maps and tables prepared by City and County of San Francisco, Department of Public Health, Environmental Health Section using ArcGIS software.

Map data is presented at the level of the census tract. The map also includes planning neighborhood names, in the vicinity of their corresponding census tracts.

Table data is presented by planning neighborhood. Planning neighborhoods are larger geographic areas then census tracts. SF DPH used ArcGIS software and a 'centroids within' methodology to convert census tracts to geographic mean center points. We then assigned census tracts to planning neighborhoods based on the spatial location of those geographic mean center points and calculated the planning neighborhood totals for the table.

Detailed information regarding census data, geographic units of analysis, their definitions, and their boundaries can be found in the HDMT at the following links:

http://www.thehdmt.org/etc/Geographic_Units_of_Analysis.pdf

http://www.thehdmt.org/data_map_methods.php

Explanation and Limitations

The change in SF income relative to regional change in income between 1990-2000 and 1990-2007 is an attempt to provide one measure of gentrification. Gentrification can be defined in a variety of ways, specifically as "The restoration and upgrading of deteriorated urban property by middle-class or affluent people, often resulting in displacement of lower-income people." (American Heritage Dictionary) or more broadly as "a process of class transformation: it is the remaking of working-class space to serve the needs of middle- and upper-class people" (Newman and Wyly, National Housing Institute, last accessed May 29, 2007: http://www.nhi.org/online/issues/142/gentrification.html). When neighborhood income change is dramatically higher than the regional income change, it can denote a disproportionate change in the neighborhood population from lower income households to higher income households.

The data illustrate that between 1990 and 2000, San Francisco's median household income increased over twice as much (2.4 times) as the nine-county regional median household income. But between 1990 and 2007, the change in San Francisco income paralleled the change in income regionally.  The Bay Area regional calculation is based on the primary metropolitan statistical area (PMSA), which includes Sonoma, Napa, San Francisco, Solano, Alameda, Santa Clara, Contra Costa, San Mateo and Marin counties. San Francisco's median income in 1990, adjusted for inflation, was $40,942 and in 2000, was $58,472.

At a neighborhood level, the increases are even more striking. For example, between 1990 and 2000, income levels in the Bayview increased 5.4 times as much as income levels increased regionally; in Potrero Hill, the increase was 7.5 times as much, and in Visitacion Valley, the neighborhood increase was highest at 33.4 times greater than the regional increase.

Looking more closely at the neighborhood data, it is apparent that a wide range of income increases occurred between 1990 and 2000. While the majority of neighborhoods experienced a higher degree of income increase than the region (e.g., Bayview, Potrero Hill and Visitacion Valley), others experienced a lower degree of income increase than the region (e.g., Downtown/Civic Center, Outer Mission, and Excelsior). And still others experienced a decrease in income altogether (e.g., Seacliff and Chinatown).

The map illustrates a finer degree of geographic detail, as it assesses the change in income at the census tract level (in contrast to neighborhood level changes) and compares that change to the regional income change. As the map illustrates, the variability in income changes are considerable across census tracts. Some small census tracts experienced significant increases in income between 1990 and 2000. However, not all increases result in very high income levels. For example, one census tract in the Southeast sector of the City experienced an income increase of greater than 24 times the regional income increase. But if we examine the 1990 and 2000 income data for that census tract more closely, we see that the 1990 income was $1,235 and in 2000 was $18,292 (data not shown). Based on this data, while the proportional increase may be quite large, the 2000 income level is still below the poverty line.

Additionally, the Census only reports median household incomes for each tract. Therefore it does not account for the low and high extreme incomes within each census tract. At the neighborhood level, median income is calculated using the median income at the census tract level, weighting for the number of households.

It is important to note that gentrification is best measured using a combination of indicators, including demographic and physical changes in the community, as well as, the extremity and rapidity of those changes (Clemmer, PSU, last accessed online at: http://www.urban-research.info/ur/pdf/Portland%20Neighborhood%20Gentrification%20Patterns2.pdf) Demographic indicators include such attributes as changes in education level, race/ethnicity, and income of individuals. Physical indicators can include such changes in housing types and prices, types of restaurants and available goods and services. While this indicator does not capture all the attributes listed above, it allows for an understanding of the disproportionate increase in income at a small geographic level in comparison to regional changes in income.

The consequences of gentrification can have both negative and positive impacts on a community. For example, a rise in higher income residents can increase the consumer power of the community and bring in much needed businesses such as grocery stores. At the same time, higher income residents can displace existing lower income residents as they are able to pay more for rents, and increased rent prices can make it more difficult for lower income residents to remain in a community. Often the original residents of a community in the process of being gentrified have limited opportunity to enjoy the increased retail and infrastructure benefits associated with the gentrification process, while at the same time they experience the risk of displacement, increased rents burdens, loss of social networks and loss of familiar neighborhood characteristics.

The positive impacts of gentrification arise from the creation of economic and racial/ethnic integration. While gentrification begins with integration of higher income residents into lower income communities, as gentrification continues, the lower income community is often displaced creating, once again, economically segregated communities. Additionally, the integration of lower income residents into higher income communities is not occurring due to economic limitations of lower income households to purchase housing in higher income communities. Therefore, displaced lower income households from gentrified communities are often left to move into lower income neighborhoods or out of the city. Thus, gentrification can further segregate communities and create entire shifts in the demographic makeup of a city.

Why is this a Community Health Indicator?

Gentrification can cause displacement. Involuntary displacement or relocation can be a stressful life event. The San Francisco Department of Public Health conducted focus groups with tenants facing eviction due to redevelopment in 2003. Discussing how she felt about an eviction notice at the, one resident stated: "We are fearful, feelings are hurt, and [we're having] difficulty speaking about displacement, stressed, sleeplessness, anxiety, and the issue has been constantly going on."

Households that are displaced often experience unhealthy situations due to the loss of social relationships within a community, the difficulties and stress associated with finding new housing that is affordable, as well as, the added time, energy and money needed to relocate. Frequent household moves have been linked with negative childhood events such as abuse, neglect, household dysfunction and increased likelihood of smoking and suicide in children.^a Frequent family relocation also leads to children repeating grades, school suspensions, and emotional and behavioral problems.^b Childhood residential instability has also been found to predict lifetime risk of depression.^c In contrast, residential stability in childhood has shown to have positive effects on health at midlife.^d Creating opportunities for affordable and safe housing forms a stable and healthy household environment which has long-term positive health implications, particularly for children.

For additional information on the connections between housing and health, visit: The Case for Housing Impacts Assessment by SFDPH, Program on Health Equity and Sustainability. Accessed online on October 19, 2006: http://www.thehdmt.org/etc/004_HIAR-May2004.pdf