Table 1.
Summary of Dependent and Independent Variables Used in the Models (From February 1st, 2020 to May 31st, 2020).
| Variables | Description | Mean | SD | Min. | Max. | |
|---|---|---|---|---|---|---|
| Dependent Variables | ||||||
| Δ Trip per person | Daily average number of trips per person compared with January 2020 (Mean: 3.326 SD:0.466) | −0.209 | 0.405 | −1.264 | 0.798 | |
| Δ Person-miles traveled | Daily average person-miles traveled compared with January 2020 (Mean: 42.952 SD:10.572) | −5.686 | 9.715 | –32.060 | 31.399 | |
| Δ Proportion of staying home | Daily average proportion of residents staying at home compared with January 2020 (Mean: 0.199 SD:0.055) | 0.048 | 0.062 | −0.088 | 0.229 | |
| Independent Variables | ||||||
| Policy | Stay-at-home order | Categorical Variables. 0: No Stay-at-home order (Reference); 1: Stay-at-home order issued without penalty or specifying enforcement (32.54%); 2: Stay-at-home order issued and enforced with a warning, and a possible fine for the repeated offense (29.35%); 3: Stay-at-home order issued and enforced with fines and possible jail time (28.55%). | – | – | 0.000 | 3.000 |
| FEMA | If COVID-19 Emergency Declaration issued, 1; else 0. | 0.277 | 0.448 | 0.000 | 1.000 | |
| Reopening order | If (partial) reopening order is issued, 1; else 0 (Reference). | 0.218 | 0.413 | 0.000 | 1.000 | |
| ARG | If the Guideline for Opening Up America Again issued, 1; else 0. | 0.361 | 0.480 | 0.000 | 1.000 | |
| COVID-19 | New cases | Daily number of newly confirmed COVID-19 cases in the county (1,000). | 0.003 | 0.025 | 0.000 | 2.155 |
| Sum cases | Daily number of accumulated confirmed COVID-19 cases in the county (1,000). | 0.127 | 1.154 | 0.000 | 77.925 | |
| Adj. new cases | Daily number of newly confirmed COVID-19 cases in the adjacent counties (1,000). | 0.020 | 0.089 | 0.000 | 4.462 | |
| Adj. sum cases | Daily number of accumulated confirmed COVID-19 cases in adjacent counties (1,000). | 0.803 | 4.878 | 0.000 | 200.167 | |
| National new cases | Daily number of newly confirmed COVID-19 cases in the nation (1,000). | 14.551 | 12.859 | 0.000 | 36.590 | |
| Temporal | Week | The day of the week, from 0 (Monday) to 6 (Sunday). | – | – | 0.000 | 6.000 |
| Weekend | If the day is weekend, 1; else 0 (Reference). | 0.290 | 0.454 | 0.000 | 1.000 | |
| Time Index | The difference in the day from the current date to February 1st, 2020. | – | – | 0.000 | 120.000 | |
| Socio-Demographic | Population density | Population density, in 103 persons/sq. mile. | 0.233 | 0.945 | 0.000 | 25.591 |
| Employment density | Job density, in 103 jobs/sq. mile. | 0.125 | 1.319 | 0.000 | 67.846 | |
| Male | The proportion of males. | 0.500 | 0.023 | 0.421 | 0.790 | |
| Age_0_24 | The proportion of people aged between 0 and 24. | 0.312 | 0.047 | 0.105 | 0.612 | |
| Age_25_40 | The proportion of people aged between 25 and 40. | 0.176 | 0.029 | 0.067 | 0.346 | |
| Age_40_65 | The proportion of people aged between 40 and 65. | 0.328 | 0.030 | 0.149 | 0.499 | |
| Race-White | The proportion of White not Hispanic or Latino. | 0.767 | 0.198 | 0.007 | 1.000 | |
| Race-Hispanics | The proportion of White Hispanic or Latino. | 0.066 | 0.112 | 0.000 | 0.944 | |
| Race-African American | The proportion of African American. | 0.093 | 0.147 | 0.000 | 0.874 | |
| Race-Asian | The proportion of Asian. | 0.013 | 0.023 | 0.000 | 0.359 | |
| Median income | The median household income, in $103/household. | 51.402 | 13.605 | 20.188 | 136.268 | |
| Army personnel | The proportion of people in armed forces. | 0.003 | 0.016 | 0.000 | 0.520 | |
| College students | The proportion of residents enrolled in college or graduate school. | 0.050 | 0.039 | 0.000 | 0.536 | |
| Incarcerated ratio | The proportion of population incarcerated. | 0.004 | 0.008 | 0.000 | 0.167 | |
| Political parties | Democrats | The proportion of Democrats in presidential candidate vote totals. | 0.316 | 0.151 | 0.031 | 0.909 |
| Republicans | The proportion of Republicans in presidential candidate vote totals. | 0.632 | 0.155 | 0.041 | 0.946 | |
| Non-voters | The proportion of non-voters. | 0.557 | 0.077 | 0.208 | 0.871 | |
| Industry (weighted by number of employees in each establishment) | Agriculture | The proportion of agriculture, forestry, fishing, hunting, mining, quarrying, oil and gas extraction, and construction sectors. | 0.090 | 0.075 | 0.000 | 1.000 |
| Retail | The proportion of retail trade and wholesale trade sectors. | 0.256 | 0.104 | 0.000 | 1.000 | |
| Educational | The proportion of educational, professional, scientific, and technical services. | 0.045 | 0.037 | 0.000 | 0.486 | |
| Finance | The proportion of finance and insurance services. | 0.053 | 0.031 | 0.000 | 0.500 | |
| Transportation | The proportion of transportation and warehousing services. | 0.064 | 0.049 | 0.000 | 1.000 | |
| Entertainment | The proportion of arts, entertainment, and recreation services. | 0.009 | 0.012 | 0.000 | 0.277 | |
| Accommodation | The proportion of food and accommodation services | 0.151 | 0.081 | 0.000 | 1.000 | |
| Health care | The proportion of health care and social assistance services. | 0.146 | 0.088 | 0.000 | 1.000 | |
| Manufacturing | The proportion of manufacturing industry. | 0.101 | 0.110 | 0.000 | 0.776 | |
| Weather | Precipitation | Daily precipitation, in mm. | 3.363 | 8.532 | 0.000 | 197.900 |
| Max. Temperature | Daily maximum temperature, in Celsius. | 16.516 | 8.968 | –22.667 | 222.800 | |
| Min. Temperature | Daily minimum temperature, in Celsius. | 4.437 | 8.415 | −36.700 | 27.250 | |
a. Italic texts: excluded variables due to multicollinearity.
b. All analyses are based on contiguous United States (i.e. Hawaii and Alaska are excluded) from February 1st, 2020 to May 31st, 2020.
c. To address the low-sampling biases, only counties with at least 1% daily sampling ratio are included in this study.
d. The adjacent counties are calculated based on the queen relationship, i.e., the county share at least one border or one vertex is defined as an adjacent county.
e. Data source:
1. The county-level socio-demographics are obtained from the 2017 American Community Survey (ACS) 5-year estimates. The industry types are from the 2018 Annual Economic Surveys. The incarcerated data are from the Bureau of Justice Statistics (BJS). The 2018 election data are from the MIT election lab (Lab, 2018).
2. The weather conditions are obtained from the US National Weather Service Forecast Office.
3. The county-level policy information are collected from different government announcements (see (Sarah Mervosh, 2020; Yuriria Avila, 2020) for a summary).
4. The virus data are from the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (CSSE, 2020).
f. On February 17th, 2020 (Washington's Birthday) and May 25th, 2020 (Memorial Day), abnormal data fluctuations are observed across the nation due to the holiday effects, we fix the outliers with linear interpolation.