May 22, 2022 -- What is gentrification? Can we measure it?

Few topics have grabbed the attention of urban scholars and policymakers like "gentrification," a process first described in Ruth Glass' 1960s work about displacement of working-class residents in London. Today, most folks define gentrification as the process by which lower-income communities are displaced by higher-income communities - this manifests as a combination of shifting business landscapes, higher taxes and rents, and increased state investment (including police presence). In the early 2000s, geographers began to point to policies and planning strategies that were rapidly accelerating gentrification while cities pointed to it as an important part of urban revitalization. Meanwhile, activists and low-income communities the world over have pointed to gentrification as perhaps the single greatest threat to the cultural and historical roots of those communities in cities.

Compounding this, cities around the world have included the expansion and spread of green space in their sustainability and resilience plans, citing the many important benefits of urban green space for cities and citizens (more on this in a future blog post). So as green space expands globally, we know with certainty that, in addition to the benefits of nearby parks and gardens, there will be important consequences for communities as gentrification continues to push residents out of their long-time neighborhoods. This means it's more urgent than ever that we study gentrification and document its links to green spaces of many forms. Despite this, one fundamental uncertainty haunts this scholarship: how do we reliably measure gentrification?

Gentrification is, as they say, one of those things that you know when you see it - in my current hometown of Nashville, it's recognizable all across the city. Old businesses close down, and trendy coffee shops or gyms open in their place. Property values climb inexorably, and rents grow much more rapidly. Government services and police presence return to disinvested streets, and contractor trucks are seen on every corner. And slowly but surely, the faces on the sidewalk are replaced by a new, wealthier crowd. All of this paints a clear, but complex picture. How do we measure all of that happening at once?

Perhaps the most well-known hallmark of gentrification is a rise in property values, rents, and evictions. For many years, scholarship and policy have used these indicators as a rough proxy for gentrification, connecting them to displacement as surely as the moving trucks. Increasingly, though, scholars are unsure that these simple measures of gentrification tell us much of the story - gentrification really begins much earlier, as long-standing communities are slowly but surely made to feel that they are no longer at home on their streets. This takes the form of an increased police presence, of shop signs changing languages, of new income or background check requirements on leases. And how do we measure all of that at the scale of a city?

In a recent paper, we adopted the data produced via a collaboration between Turning the Corner and Data Driven Detroit, an effort where they mapped the potential for gentrification across the city. After mapping urban gardens all over Detroit, we compared their locations to what D3 and Turning the Corner flagged as areas at risk of gentrification. Surprisingly, we found no relationship. If anything, several of the indicators seemed to suggest that some of the neighborhoods with lots of gardens were more stable and less likely to undergo rapid change. What's going on here?

Well, the story is complex, and you'll have to read my upcoming blog post on Detroit for all the details, but one of the possibilities is that we just didn't measure gentrification very well. Wait a minute, wasn't the whole point of Turning the Corner's work that they were more effectively measuring the risk of gentrification? Yes, but since then, more scholarship has pointed out that even complex, mixed-method indicators are at risk of underestimating gentrification, especially early in the process. In their recent work in LA, Loukaitou-Sideris and colleagues found that a city-sponsored, mixed-methods indicator did a pretty good job of identifying late-term gentrification - but was nearly blind to early warning signs experienced and reported by residents. We haven't been able to test if this is what happened in Detroit - but the possibility of it raises more red flags in the search for effective measurement of gentrification and raises more roadblocks in the study of urban green space and its effects.

So what's the big punchline here? Is there a magical solution to this stumbling block in modern research? No. The big punchline, if there is one, is that researchers must work alongside communities to continue to develop better indicators of gentrification. For as long as there has been study of gentrification, the best measurement of it has been based in the experiences of community members. Projects like Turning the Corner are taking important steps to combine these experiences with city-wide, quantitative measurements. As always, though, there's still work to do, and for communities facing rising costs and imminent displacement, that work can't happen soon enough.

Relevant readings:

Classic readings on gentrification:

Glass, R. (1964). London: Aspects of change. MacGibbon & Kee.

Lees, L. (2012). The geography of gentrification. Progress in Human Geography, 36(2), 155–171. https://doi.org/10.1177/0309132511412998

Green gentrification:

Anguelovski, I., Connolly, J. J., Garcia-Lamarca, M., Cole, H., & Pearsall, H. (2019). New scholarly pathways on green gentrification: What does the urban ‘green turn’ mean and where is it going? Progress in Human Geography, 43(6), 1064–1086. https://doi.org/10/gfc96p

Wolch, J. R., Byrne, J., & Newell, J. P. (2014). Urban green space, public health, and environmental justice: The challenge of making cities ‘just green enough.’ Landscape and Urban Planning, 125, 234–244. https://doi.org/10.1016/j.landurbplan.2014.01.017

Kim, S. K., & Wu, L. (2021). Do the characteristics of new green space contribute to gentrification? Urban Studies, 0042098021989951. https://doi.org/10/gh39xm

Hawes, J. K., Gounaridis, D., & Newell, J. P. (2022). Does urban agriculture lead to gentrification? Landscape and Urban Planning, 225, 104447. https://doi.org/10.1016/j.landurbplan.2022.104447

Modern measurement of gentrification:

Cohen, M., & Pettit, K. L. S. (2019, April 19). Guide to Measuring Neighborhood Change to Understand and Prevent Displacement. Urban Institute. https://www.urban.org/research/publication/guide-measuring-neighborhood-change-understand-and-prevent-displacement

Loukaitou-Sideris, A., Gonzalez, S., & Ong, P. (2019). Triangulating Neighborhood Knowledge to Understand Neighborhood Change: Methods to Study Gentrification. Journal of Planning Education and Research, 39(2), 227–242. https://doi.org/10/gm72td

Martin, R. W. (2017). A Quantitative Approach to Gentrification: Determinants of Gentrification in US Cities, 1970-2010. Department of Insurance, Legal, Studies, and Real Estate, Terry College of Business, University of Georgia.

Quesnelle, S., Rubio, A., & Urban, N. (2019). Final Local Analytical Report – Detroit (Turning the Corner). Data Driven Detroit. https://www.neighborhoodindicators.org/sites/default/files/publications/TTC_ThirdEdition_20190204.pdf