Working Paper: NBER ID: w29021
Authors: Emily Breza; Fatima Cody Stanford; Marcella Alsan; Burak Alsan; Abhijit Banerjee; Arun G. Chandrasekhar; Sarah Eichmeyer; Traci Glushko; Paul Goldsmith-Pinkham; Kelly Holland; Emily Hoppe; Mohit Karnani; Sarah Liegl; Tristan Loisel; Lucy Ogbunwobodo; Benjamin A. Olken; Carlos Torres; Pierreluc Vautrey; Erica Warner; Susan Wootton; Esther Duflo
Abstract: During the COVID-19 epidemic, many health professionals started using mass communication on social media to relay critical information and persuade individuals to adopt preventative health behaviors. Our group of clinicians and nurses developed and recorded short video messages to encourage viewers to stay home for the Thanksgiving and Christmas Holidays. We then conducted a two-stage clustered randomized controlled trial in 820 counties (covering 13\nStates) in the United States of a large-scale Facebook ad campaign disseminating these messages. In the first level of randomization, we randomly divided the counties into two groups: high intensity and low intensity. In the second level, we randomly assigned zip codes to either treatment or control such that 75% of zip codes in high intensity counties received the treatment, while 25% of zip codes in low intensity counties received the treatment. In each treated zip code, we sent the ad to as many Facebook subscribers as possible (11,954,109 users received at least one ad at Thanksgiving and 23,302,290 users received at least one ad at Christmas). The first primary outcome was aggregate holiday travel, measured using mobile phone location data, available at the county level: we find that average distance travelled in high-intensity counties changed by -0.993 percentage points (95% CI -1.616, -0.371, p-value 0.002) the three days before each holiday. The second primary outcome was COVID-19 infection at the zip-code level: COVID-19 infections recorded in the two-week period starting five days post-holiday declined by 3.5 percent (adjusted 95% CI [-6.2 percent, -0.7 percent], p-value 0.013) in intervention zip codes compared to control zip codes.
Keywords: No keywords provided
JEL Codes: D83; I12
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| social media ads (M37) | average distance traveled (R41) |
| social media ads (M37) | COVID-19 infections (I14) |
| high-intensity counties (R23) | average distance traveled (R41) |
| high-intensity counties (R23) | COVID-19 infections (I14) |