Communities where neighborhood change is anticipated can prepare by identifying the appropriate indicators and measuring them over time to determine which strategies or interventions are needed to manage change that has an adverse impact on lower-income populations or neighborhoods. First, municipalities must establish a current demographic and residential baseline. Second, they must observe and monitor any changes to this baseline. This can be done, as it was in Somerville, by tracking data that measures the municipality’s demographic diversity, housing cost burden, livability, auto ownership, and travel behavior. Importantly, these indicators aim to distinguish between natural housing turnover and displacement as a result of decreasing affordability, both of which can be a consequence of neighborhood change. Together, the following indicators can help position municipalities to better understand how they are changing and, in doing so, plan to capitalize on new investment and mitigate any negative impacts.
Demographics & Migration
Number and share of low-income households in the municipality, and share relative to the sub-region and/or region
A decrease in economic diversity as a result of increasing rents and a restricted rental supply, for example, would be a negative impact of neighborhood change. Tracking the number and share of low-income households can help gauge the degree to which displacement or replacement is occurring and whether existing mitigation strategies are effective. A stable or increasing number of low-income households indicates a low rate of displacement or replacement by higher-income households; a declining number may mean such processes are underway. A stable or increasing share of low-income households means that the municipality has created new affordable housing opportunities.
Data Source: Estimates of the number of low-income households (earning 80% of area median income or below) are published by the US Department of Housing and Urban Development (HUD) in the Comprehensive Housing Affordability Strategy dataset (CHAS).
Racial and Ethnic Diversity
Municipality’s population of color (number and share), and share relative to the sub-region and/or region
While displacement is largely driven by income disparities, the fact that higher-income households are disproportionately white and lower-income households are disproportionately non-white means that displacement risk also carries implications for the racial diversity of a community. A stable or increasing number of residents of color in a municipality indicates a low rate of displacement or replacement by white residents; a declining number may mean such processes are underway. An increasing share of a municipality’s population of color indicates increasing diversity; a decreasing share means that relatively fewer residents of color have access to the municipality.
Data Source: US Census
Lower-income households as a share of all out-migrant households and as a share of all in-migrant households; non-white individuals as a share of all out-migrants and as a share of all in-migrants
The composition of in- and out-migrants to a municipality has a substantial impact on its demographics. Changes in the characteristics of in-migrants could cause a rapid demographic transition, even if the pace of outmigration remains constant. If low-income households and people of color begin moving out of a municipality at a higher rate, then those populations will dwindle. An increasing share of moderate-to-high-income households or white, non-Hispanic people among in-migrants—and in particular a greater share relative to the current population—indicates that demographic replacement is occurring. Conversely, an increase in the share of low-income households and people of color among the out-migrants is a clear indication of displacement.
Data Source: Public Use Microdata Sample (PUMS)
Housing & Households
Housing Cost Burden
Percent of low-income households with high housing cost burden, number of low-income households not cost burdened, and rate of cost-burdened low-income households relative to the sub-region and region
The size of the population most vulnerable to displacement could itself change over time, perhaps due to rising local housing costs or broader economic shifts. If the share of lower-income households who are cost burdened (meaning they pay 30% or more of their annual household income on housing costs) rises, then this population is facing increasing difficulty finding housing that is affordable to them. If the share declines, it could mean that lower-income households are more easily managing to secure housing they can afford. However, it could also mean that such households have left the municipality. Consequently, we suggest also tracking the number of non-cost burdened low-income households. An increase in this number means that more low-income households can stay in the city without being unduly strained by high housing costs. It is also revealing to compare incidence of cost burden to the sub-region and region in order to determine if the municipality is following regional trends or becoming more of an outlier.
Data Source: American Community Survey
Families with Children
Number of families with children; municipality’s share of sub-region and region’s families with children
Real estate trends in transit-oriented areas can make it difficult for families to secure housing that meets their needs and that they can afford. Development of smaller units and subdivision of large homes into multiple condominiums may result in a limited stock of family-friendly housing. While smaller units can be an appropriate and desirable choice for single people, young professionals, and seniors, they often do not provide enough space for households with children. Meanwhile, larger housing units in these areas tend to be high-cost options. Tracking families with children increases understanding of how the changing housing stock is accommodating this subset of the population. A smaller number of families with children in the municipality means that this population is on the decline. Since the number of such households is likely to decline region-wide as a result of broader trends towards shrinking household size, it is also useful to compare figures at the municipal level to those at the sub-regional and regional to see if the local decline is occurring at a faster rate.
Data Source: Decennial Census
Homeownership gap between white and non-white households, and relative to the sub-region and/or region
Renter households are particularly vulnerable to displacement as housing markets experience inflation. Since people of color make up a disproportionate share of renter households, they are at a greater risk. Therefore, homeownership rates should be calculated for white and minority households, followed by the gap between them (for example, subtract the percentage of Hispanic householders who own from that of white, non-Hispanic householders). A greater parity in homeownership rates between whites and people of color means that this inequity is on the decline, while an increase in the discrepancy means it is increasing.
Data Source: Decennial Census
Designated Affordable Housing
Number and share of deed restricted affordable housing units in the municipality, and number and share of affordable units that could expire (i.e. are not affordable in perpetuity)
Designated affordable housing is a critical resource for low-income households. If the absolute number of deed-restricted affordable units in a municipality is rising and that figure as a share of total units is stable, then the municipality is at least keeping pace with, if not reducing, the scale of the affordability challenge relative to its overall population growth. If the absolute number of subsidized units is growing but its share of total units is declining, then the municipality should consider strategies to increase affordable housing production. If the number and share of affordable units are both decreasing, major efforts are needed. Such a decrease could be a consequence of expiring affordable units; municipalities should be forward-thinking and take note of units that are not affordable in perpetuity.
Data Source: MA Department of Housing and Community Development Chapter 40B Subsidized Housing Inventory, Census housing unit count
Vehicle Ownership and Mileage
Registered vehicles per household and vehicles miles traveled per household
If neighborhood change is prompted by investment in public transit infrastructure, then a decrease in the rate of vehicle ownership per household would indicate reduced dependence on automobiles and an increase in attractive alternative transit modes. Meanwhile, an increasing vehicle ownership rate indicates that transit options are not sufficiently meeting resident need, or that high-income, less transit-dependent households make up an increasing share of the population. Estimated daily mileage per household indicates actual vehicle usage; a decline over time would indicate improved alternative transit modes.
Data Source: Massachusetts Vehicle Census (MAPC)
Commute Mode Share
Percent of workers commuting by car, transit, bike, and foot
An increase in the share of workers commuting by transit, bike, or foot indicates that people are able to reduce their dependence on private vehicles for commuting to work, which is the trip purpose that accounts for the largest share of unique riders on public transit. Commuting via public transit has vastly outweighed commuting by bike or foot for the last several decades, and all three modes tend to rise and fall in tandem because the conditions that support transit usage are strongly related to those that support biking or walking to work. This indicator should be evaluated in conjunction with an awareness of broad economic conditions, however, as events such as a recession or a spike in gasoline prices can also result in modal shifts.
Data Source: American Community Survey
Transit Commute Times
Average commute time for municipality’s transit commuters; percent of transit commutes 30 minutes or longer; percent of transit commutes to jobs within the municipality 30 minutes or longer
Often, areas with rail transit are served by public buses. Because of longer wait times and more frequent stops, bus commutes typically take more time than rail commutes. In theory, the introduction of rail transit would shorten commute times for residents in close proximity to station areas. Commute time to employment within the municipality indicates whether transit is a viable option for job-holders.
Data Source: American Community Survey