Table 2.
Regressions for COVID Deaths per Capita
| (1) | (2) | (3) | (4) | |
|---|---|---|---|---|
| Estimation method | SUR | SUR | Instruments | Instruments |
| Period I: 3/19/21–6/13/21 | ||||
| vaccination rate | −.0010 (.0014) | −.0011 (.0014) | −.0057 (.0086) | −.0057 (.0086) |
| Period II: 6/13/21–9/6/21 | ||||
| vaccination rate | −.0042*** (.0008) | −.0041*** (.0008) | −.0041*** (.0012) | −.0041*** (.0012) |
| Period III: 9/6/21–12/1/21 | ||||
| vaccination rate | −.0092*** (.0016) | −.0100*** (.0017) | −.0093*** (.0021) | −.0096*** (.0021) |
| vaccination rate, older | -- | −.0060* (.0032) | -- | −.0063 (.0047) |
| joint p-value | 0.000 | 0.000 | ||
| p-value for equal coeffs | 0.24 | 0.44 | ||
| Period IV: 12/1/21–2/25/22 | ||||
| vaccination rate | −.0023** (.0010) | −.0023** (.0012) | −.0025* (.0014) | −.0031** (.0015) |
| vaccination rate, older | -- | −.0023 (.0015) | -- | .0016 (.0017) |
| joint p-value | 0.08 | 0.13 | ||
| p-value for equal coeffs | 0.99 | 0.39 | ||
| Period V: 2/25/22–5/22/22 | ||||
| vaccination rate | −.0002 (.0007) | .0000 (.0007) | .0004 (.0010) | .0006 (.0009) |
| vaccination rate, older | -- | −.0012 (.0012) | -- | .0010 (.0014) |
| joint p-value | 0.58 | 0.44 | ||
| p-value for equal coeffs | 0.32 | 0.23 | ||
| R-squared | .28 .65 .65 .65 .60 | .28 .65 .66 .65 .61 | .16 .65 .65 .65 .59 | .16 .65 .66 .65 .60 |
| s.e. | .0003 .0003 .0006 .0004 .0003 | .0003 .0003 .0006 .0004 .0003 | .0003 .0003 .0006 .0004 .0003 | .0003 .0003 .0006 .0004 .0003 |
Notes: Sample is 50 U.S. states plus District of Columbia. Sample dates shown in the left-most column refer to the dependent variable. This variable is the change in cumulative reported COVID-related deaths per capita over each period (values expressed per year). Vaccination rate in columns 1 and 3 is the fraction of the population fully vaccinated against COVID-19 (not counting booster shots). This variable is lagged 14 days from the dependent variable and is entered as an average over each period, as described in Table 1. In columns 2 and 4, vaccination rate is the fraction of the population fully vaccinated over roughly the last 6 months plus the fraction fully vaccinated earlier who have received booster shots. In these columns, “vaccination rate, older” is the fraction fully vaccinated roughly 6 or more months in the past less the fraction who have received booster shots. Other explanatory variables, shown in Table 1, are fraction of population aged 65 and over in 2020, life expectancy at birth in 2018, fraction of population aged 25 and over who completed high school or more in 2019, fraction of population black in 2020, urbanization rate in 2010, and average maximum temperature over periods corresponding to the dependent variable. Coefficients on these variables, constant terms, and the vaccination rates differ across periods. Standard errors of coefficient estimates are in parentheses. SUR (seemingly-unrelated regression) allows for a different error variance in each period and for correlation of the error terms across periods. s.e. is the standard error of each regression. In columns 1 and 3, instrumental estimation (three-stage least-squares) uses as the excluded instrument the fraction of the population voting in 2020 that voted Republican (as shown in Table 1). In columns 2 and 4, the instrument list also includes the difference in the vaccination variable for the current period from that in the period roughly 6 months earlier.
Significant at 1%,
significant at 5%,
significant at 10%.