Density mapping of dating app users across time and space in Mumbai, India

Background: Dating apps make it easier and seemingly safer for men who have sex with men (MSM) to find partners. How, then, can HIV programs use available data to better align HIV outreach activities to the specific times and locations of MSM dating app usage while maintaining safety and privacy?
Methods: The USAID and PEPFAR-supported LINKAGES project in India created density maps of location-based dating app users in Mumbai to identify concentrations of users and enhance program coverage. Using ArcGIS software, Mumbai was overlaid with a gridwork of latitude/longitude points each two kilometers apart (374 points), and a second group of points at 1 kilometer distance (410 total). Data collectors used Android phones and an app to set their phone''s Global Positioning System (GPS) location for each of the plotted coordinates, then opened Grindr to count the number of nearby online users. The number of online users within one kilometer of each 2-kilometer separated point was collected three times daily, over five days of one week in October 2017. The process was repeated in December 2017 for online users within 500 meters of each 1-kilometer separated point over 7 days. Excel''s 3D maps plug-in generated short videos animating the changing density of Grindr users across the week and area of Mumbai. These activities never collected individual location data, and data are not granular enough to target people in physical settings.
Results: An average of 3,810 online Grindr users were counted across metropolitan Mumbai. The highest number of online users was counted on midday Saturday and Sunday. On weekdays, counts increased later in the day. The second mapping revealed high-density locations of dating app use including several time-bound areas and 6 consistent areas with 23 or more online users within 500 meters of each coordinate (Figure 1).
Conclusions: This activity successfully identified physical clusters of online MSM at specific times of dating app usage, and estimated total online users in Mumbai. The LINKAGES program in India used these results to guide outreach to MSM on Grindr at high density locations through peer- and advertisement-based approaches that will be combined with location-specific referrals for services.


Figure 1: Density mapping in Mumbai compared - 1km radius sampling (left) versus more precise 500m radius sampling (right) showing clear high-density
[Figure 1: Density mapping in Mumbai compared - 1km radius sampling (left) versus more precise 500m radius sampling (right) showing clear high-density ]

B. Eveslage1, P. Shah2, C. Parker1, B. George3, J.J. Baishya4
1FHI 360, Washington, United States, 2FHI 360, LINKAGES, New Delhi, India, 3FHI 360, Country Director, New Delhi, India, 4USAID, New Delhi, India