When the data were analyzed, a striking pattern emerged: most neighborhood features had barely changed over time. Seventeen of the twenty variables assessed were unchanged at over 90 percent of locations. Structural features such as sidewalks, vacant lots, and street lighting were especially consistent, while more transient features such as litter, graffiti, and building repair needs exhibited greater variability over time. This variability was not patterned by place, though–for example, whether any litter was visible changed in about a quarter of locations–but overall prevalence at the city level remained nearly constant. The clearest consistent change over time was the expansion of bicycle infrastructure, which increased across all four cities in line with national investments in cycling facilities and bike-sharing programs.
Dr. Mooney emphasized that: “generally speaking, not much changed over 10 years. This is important because, as scientists, we want to measure conditions at the time people experience them. For folks using Street View to assess neighborhood conditions, it feels like a challenge that we can't control when Google drove the car past a location. But it turns out that for a lot of measures in a lot of places, it really doesn't matter much.” In other words, while dramatic neighborhood transformations—such as those seen in Seattle’s South Lake Union over the past two decades—certainly occur, many residential areas, like Queen Anne or Beacon Hill, remain visually consistent, reducing the risk of bias in longitudinal studies not specifically targeting residents of areas undergoing rapid change..
The analysis also explored whether neighborhood income levels influenced the rate of change. While features of disinvestment were more common in lower-income areas at any single point in time, the pace of change was similar across income levels. This suggests that although inequality in neighborhood conditions persists, it does not manifest as differences in temporal stability of features.
What does all this mean for public health research? By demonstrating that most built environment features remain stable over a decade, the study provides reassurance that modest mismatches between imagery dates and research timelines are unlikely to compromise findings in neighborhoods not undergoing rapid redevelopment. This allows researchers to leverage GSV as a scalable and efficient tool for large epidemiological studies, linking neighborhood conditions to health outcomes such as diabetes incidence or physical activity.
At the same time, the study raises new questions. As Dr. Mooney reflects, “Is there a way to identify where changes have happened, so we can update our neighborhood measures only where it really matters?” This question points to the future direction of research: developing strategies to detect change hotspots, allowing resources to be focused where temporal mismatches could truly influence results. He also highlights the broader significance of linking Street View-based measures of disinvestment to health outcomes within the HCHS/SOL cohort. Such work will allow researchers to explore how environmental neglect—visible in vacant lots or poorly maintained buildings—may affect behaviors such as physical activity and contribute to chronic health conditions.