Visualizing density
Density can be a polarizing term when discussing housing. For some, it can evoke notions of skyscrapers and overcrowding, and the word density is often weaponized to drum up fear that something damaging and inappropriate is being proposed in a community. For others, there is an appreciation that some of our favorite places are shaped by higher density levels. Main streets, town centers, and the urban places that form our cultural centers rely on density and a mix of uses to create their strong sense of place.
Density is also a measurement; every piece of land and every neighborhood has a level of housing density that can be quantified. To successfully plan for the kinds of neighborhoods and communities we want to live in, we must be able to understand and measure the level of housing density needed to support them.
To better inform conversations about neighborhood form and address this important data need, MHP’s Center for Housing Data (CHD) created Residensity, an interactive map platform that allows visitors to measure and evaluate housing counts and residential density on any piece of land in Massachusetts. With a click of a mouse, users can draw custom neighborhood boundaries on the map and retrieve a summary of the types and densities of housing in that area, along with an estimate of overall neighborhood density.
Since CHD launched Residensity in 2023, visitors have used the site to answer important planning and development questions. Residents explored the density of their neighborhood. Planners compared existing housing stock with what zoning allowed or took note of what kinds of development their town already had. Affordable housing advocates utilized the website to provide technical support to communities addressing issues surrounding new housing development.
Residensity has been a particularly indispensable tool for communities required to comply with the state’s landmark MBTA Communities Law (3A), which requires cities and towns served by public transit through the MBTA to revise zoning rules to make multifamily housing easier to create at a minimum neighborhood density of 15 homes per acre. Residensity provides a mental framework for what 15 homes per acre looks like. With Residensity, community members, policymakers, and housing developers alike have been able to leverage thousands of examples of existing housing density to highlight how communities across the state have achieved — or in many cases exceeded — 15 homes per acre through a variety of housing types and a diversity of land uses.
“As a technical assistance provider, I used and encouraged planners to use Residensity to identify existing parcels at a density of 15 units per acre within their towns and to use images of those homes in their presentations to demystify density,” said Citizens’ Housing and Planning Association (CHAPA) MBTA Communities Engagement Manager Lily Linke. “So many people think 15 units per acre equals skyscrapers. So having those reference images was great, especially for smaller scale developments.”
The CHD team has provided programmatic and analytical support to MHP’s Community Assistance team as it developed materials and resources for the technical assistance program known as “3A TA.” Both teams have worked closely with communities to identify their districts, gauge current density, determine zoning requirements, and develop public information materials.
“We love Residensity!” said Joyce Mandell, regional organizer at Abundant Housing Massachusetts (AHMA), a nonprofit organization that supports a network of grassroots pro-housing groups across the state. “It’s an essential tool for educating people about the look and feel of density.”
Mandell said one of the most popular workshops for the AHMA network was a training from the CHD team on the use of Residensity and DataTown, another site developed by CHD which collects and presents data at the community level. Supported by data from these tools, “advocates were then able to go around in their town and point out examples of 15 homes per acre. The fear lessens when people can say, ‘hey, we already have this kind of missing middle housing in our town!’”
Residensity has become central to the conversation around local housing issues, meeting people and communities where they are in their housing advocacy work and compliance with state zoning requirements. But Residensity is not just a website; it’s backed up by a robust and innovative dataset that includes the location, typology, and density of housing on every one of the over two million parcels across the Commonwealth, driven by a novel methodology developed by the Center for Housing Data team. This underlying dataset is being leveraged to support innovative research that brings new insights to difficult questions and intractable policy problems.
One example is a collaboration with Way Finders, a Springfield-based nonprofit affordable housing organization, and the Western Massachusetts Housing Coalition, a regional association of housing, planning, and governmental groups focused on expanding affordable housing opportunities across western Massachusetts. After extensive field work that included site visits, interviews, and multiple stakeholder meetings facilitated by Way Finders and the Western Massachusetts Housing Coalition, the CHD team has used the Residensity dataset and other sources to paint a fuller picture of housing challenges and opportunities in the region.
“We’re using data to measure the scale and scope of these problems, refine some of their ideas, and ultimately provide materials that will help our partners advocate for policies and resources Western Massachusetts needs,” said CHD Director Tom Hopper.
The region is tackling several challenges, including an aging housing stock, increasing housing costs, growing demand for housing, and an increase in investor purchases and speculation in the rental housing market. The confluence of these factors has led to worsening affordability and increased housing instability. CHD is working to classify parcels relative to their suitability for being developed or redeveloped as housing and will produce an interactive data tool and a research document that presents key findings on properties or neighborhoods at risk for speculation by investor developers.
“The work with CHD is enabling us to better and more comprehensively understand the development potential in our region,” said Way Finders President and CEO Keith Fairey. “CHD’s data capabilities coupled with their willingness to ground their work by engaging with us and other key stakeholders in the region through site visits, regular updates, and more have ensured that the final product will be useful and impactful.”
Residensity’s impact has been significant far beyond the borders of Massachusetts. The precedent-setting tool has been recognized on a global level. The Center for Housing Data has been honored by Esri, the world leader in Geographic Information Systems (GIS) technology, with a Special Achievement in GIS (SAG) award.
The CHD team is excited to continue fulfilling its mission of bringing data-driven insights to pro-housing groups and advocates and using mapping and other types of information to support the creation and expansion of great neighborhoods and vibrant places across Massachusetts.
CHD's Matija Jankovic, Ellen Marya, and Tom Hopper were honored with a Special Achievement in GIS award from Esri.
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