Many researchers have analyzed trends in housing and transportation costs across metropolitan areas. The Boston Foundation’s “Boston Housing Report Card,” for instance, has long been used by advocates and policymakers to inform a better understanding of the area’s housing needs. Complementing research like this, the Brookings Institution Urban Markets Initiative developed the first Housing and Transportation Index to help users analyze housing and transportation costs together in one place.

The original Brookings tool gave planners and housing advocates a new, accessible way to understand visually the cost-of-living across the US. Since then, work maintaining and improving the Index has moved to the Center for Neighborhood Technology, and has broadened to include a host of other metrics.

The tool’s housing and transportation cost measure ends up telling a pretty interesting story about Boston, in particular. Among the 25 largest cities in the country, Boston ranks 13th most expensive for housing costs as a percent of income (at “Regional Typical,” or median, income levels). It is important to note here that part of the reason why Boston ranks 13th on this measure, and not even higher, is that this measure factors in typical income levels. So while housing costs are very high in Boston, these are offset somewhat by our higher income levels. Interestingly, this story changes pretty significantly when we also take transportation costs into account, with Boston’s ranking dropping from 13th to the 23rd most expensive large city in the nation (Table 1). The tool also allows users to do a similar set of analyses for people at lower income levels, referred to as “Regional Moderate” income levels by the Index (incomes that are 80% of Regional Typical). When looking at housing and transportation costs across this Regional Moderate metric, Boston remains 23rd among the 25 largest US cities.

Such a finding suggests that our extensive public transit system contributes significantly to reducing overall costs of living in Boston. Though housing costs in Boston are relatively high as a percentage of household income, when transit costs are incorporated our overall cost-of-living increases by only 11 percentage points. Only New York and Washington have lower increases – both of which have their own extensive transit networks.

The tool also allows users to identify the number of households paying over 45% of their income on housing (30%) and transit (15%), and locate those households within the region. These are based on two factors. The first 30% is based on a common consensus in the housing community on what a cost-burdened household looks like, while the second 15% draws from the Brookings and Center for Neighborhood Technology analysis of transit costs across the US. That analysis suggests households can afford spending at most 15% of their income on transit before it becomes financially difficult. Here in Boston, 15.1% of households spend more than the 45% income threshold on housing and transportation.

To compare the experiences of people at different income levels, the Index creates three sample types, two of which are mentioned above. These will always be specific to the area being investigated – whether Boston, Buffalo or San Francisco. The first, the “Regional Typical” Boston household, features an annual income of $73,180, which represents median household income in Boston. The second sample income type, the “Regional Moderate” household, falls to $58,544. This metric is used to show how conditions change for households earning below the median, and is defined by the Center for Neighborhood Technology (CNT) as 80% of Regional Typical income. The third sample featured is a “National Typical” (national median) household with income of around $53,000. Brookings, and subsequently the CNT, used these values to control for their impact on transportation costs. Both the incomes and transportation costs mentioned above are determined through a combination of American Community Survey data and other sources, such as the Origin-Destination Employment Statistics (LODES) data set.

These views allow us to compare housing and transportation costs across different income brackets as well as across neighborhoods. Take Quincy, for instance. At the National Typical income level, residents would pay 57% of their income on housing and transportation (as in Figure 1), while Bostonians would pay roughly 50% of theirs.

For Regional Typical households that earn more money than Regional Moderate households, housing and transportation costs consequently comprise a significantly smaller proportion of their overall income. At the Regional Typical level, Bostonians pay 38% of their income – 27% in housing and 11% in transportation – on cost-of-living expenses (Figure 2). Households in other cities within the region don’t fare quite as well as Boston does. For Quincy, housing and transportation costs run at 42% of a resident’s income at Regional Typical levels. Comparably sized Seattle, shown in Table 1, finds that residents pay 46% of their income on housing and transportation costs. This is a significant jump over Boston’s own, even as the Regional Typical income for Seattle is about $5,000 less than here. Through the tool, these variables can be further broken down by census tracts, allowing users to compare affordability for neighborhoods within a city.

The tool allows users to do more than just analyze housing and transportation costs. For instance, it tracks other measures such as average greenhouse gas output by household and average cars owned per household. It also provides composite scores measuring access to jobs and public transportation. And this is only a partial accounting of all that’s available.

The Housing and Transportation Index is a useful, flexible tool for the urban planner, researcher or policy wonk – one that allows the visualization of city information over a wide range of topics. In the era of big data, it’s not enough merely to present statistics, it is context that is key to our understanding of how policy changes can affect the real world. With tools like the Housing and Transportation Index by the Center for Neighborhood Technology, practitioners can directly communicate information about the neighborhoods and communities they target, to the neighborhoods they target, improving and informing policy choices that better serve these communities.