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Acoustic gunshot detection systems: a quasi-experimental evaluation in St. Louis, MO

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The primary aim of this study is to provide an evaluation of St. Louis’ Acoustic Gunshot Detection System’s (AGDS) ability to reduce gun violence.


The study design is a quasi-experimental longitudinal panel study. We measure a variety of gun-related offenses across multiple treatment and control neighborhoods using a difference-in-difference approach. Because treatment neighborhoods were added to the experiment over time, changing experimental conditions, three separate study periods were examined.


Results indicate AGDS has a mixed relationship to police response time and does not significantly reduce violent crime levels in any of the study periods. We do find consistent and substantial reductions (around 30%) in citizen-initiated calls for service for shots fired, but once new calls for AGDS are added, an overall 80% increase in gunshot responses is found.


Although the study is limited to one city, results indicate AGDS may be of little benefit to police agencies with a pre-existing high call volume. Our results indicate no reductions in serious violent crimes, yet AGDS increases demands on police resources.

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Correspondence to Dennis Mares.

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Table 4 Neighborhood comparison, treatment, control, and other areas
Table 5 AGDS and arrests in St. Louis and additional cities. Sources: Drange (2016) and Koren (2018)
Fig. 2
figure 2

CCTV (2019) and Violent Crime (2013–2018) Kernel densities. Camera densities are represented blue (least) to purple (most), violent crime densities are represented by green (least) to red (most)

Fig. 3
figure 3

AGDS and citizen-initiated calls for shots fired, all treatment areas (2007–2017). Changes in experimental conditions occurred in August 2008, March 2013, and July 2016 respectively. Left-hand scale denotes counts of calls for service, right-hand scale denotes percent AGDS

Fig. 4
figure 4

Changes in police response times (in minutes) in treatment areas, citizen-initiated shots fired (SHOTS) and AGDS

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Mares, D., Blackburn, E. Acoustic gunshot detection systems: a quasi-experimental evaluation in St. Louis, MO. J Exp Criminol 17, 193–215 (2021).

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