Table 2 Regression-estimated impact of being selected as a treatment zip code in the Philly Vax Sweepstakes on weekly first-dose COVID-19 vaccinations per 100,000 people

From: A citywide experiment testing the impact of geographically targeted, high-pay-off vaccine lotteries

 

Model 1

Model 2

Model 3

Model 4

β

P

β

P

β

P

β

P

Treatment Zip Code 1 during treatment (19126)

61

       

(20)

0.008

      

[38]

0.133

      

{65}

0.350

      

Treatment Zip Code 2 during treatment (19133)

  

19

     
  

(17)

0.288

    
  

[48]

0.705

    
  

{54}

0.728

    

Treatment Zip Code 3 during treatment (19142)

    

−102

   
    

(35)

0.010

  
    

[66]

0.148

  
    

{89}

0.253

  

Treatment zip codes during treatment (pooled)

      

−4

 
      

(40)

0.929

      

[45]

0.936

      

{45}

0.936

Observations

270

 

270

 

270

 

300

 

R2

0.93

 

0.93

 

0.93

 

0.93

 
  1. This table reports a series of difference-in-differences models relying on ordinary least squares regressions to predict a zip code’s weekly first-dose COVID-19 vaccinations per 100,000 adult residents. The predictor variables in each regression include zip code fixed effects, week fixed effects and an indicator that takes on a value of 1 during the weeks when a treatment zip code of interest was eligible for rewards and 0 otherwise. Standard errors have been estimated clustered by zip code (first, in parentheses), clustered by week (second, in brackets) and robustly without clustering (third, in braces) for all four models. Models 1–3 include 18 zip code clusters and 15 week clusters. Model 4 includes 20 zip code clusters and 15 week clusters. All t-tests are two-sided.