Table 1.
The estimation results of the GAM models. bs, function used in the definition of smooth terms; e.d.f., estimated degrees of freedom; F, F-test value; fs, factor smooth interactions; re, random effects; s, smooth term.
| models | daily average number of trips per person |
daily average person-miles travelled |
||
|---|---|---|---|---|
| parametric coefficients | estimate (s.e.) | t-value | estimate (s.e.) | t-value |
| (intercept) | 0.025 (0.023) | 1.051 | −2.690 (0.488) | −5.511*** |
| stay-at-home order issued without penalty or without specifying enforcement | −0.122 (0.026) | −4.774*** | −1.503 (0.506) | −2.971** |
| stay-at-home order issued and enforced with warning, and possible fine for repeated offence | −0.125 (0.025) | −4.936*** | −0.883 (0.503) | −1.754. |
| stay-at-home order issued and enforced with fine and possible jail time | −0.167 (0.024) | −6.865*** | −1.311 (0.484) | −2.710** |
| daily number of newly confirmed coronavirus cases in the states (1000) | −0.031 (0.010) | −3.194** | 0.304 (0.187) | 1.629 |
| daily number of newly confirmed coronavirus cases in the adjacent states (1000) | −0.013 (0.010) | −1.264 | 0.063 (0.200) | 0.316 |
| daily number of newly confirmed coronavirus cases in the USA (1000) | −0.028 (0.002) | −12.140*** | −0.282 (0.039) | −7.179*** |
| state governor approval rate (%) | −0.001 (0.001) | −0.402 | −0.021 (0.032) | −0.669 |
| weekend | 0.140 (0.035) | 3.998*** | 1.823 (0.787) | 2.317* |
| approximate significance of smooth terms | e.d.f. | F | e.d.f. | F |
| s (time index) | 8.839 | 566.409*** | 8.849 | 490.081*** |
| s (week) | 4.064 | 61.017*** | 4.708 | 42.043*** |
| s (state, bs = ’re’) | 0.870 | 0.019*** | 0.009 | 0.000*** |
| s (time index, state, bs = ’fs’) | 108.031 | 4.883*** | 122.700 | 11.454*** |
| s (stay at home order, state, bs = ’re’) | 19.430 | 0.325*** | 27.100 | 0.566*** |
| model goodness-of-fit | ||||
| R2 (adj.) | 0.882 | 0.919 | ||
| deviance explained | 0.887 | 0.923 | ||
p < 0.1; *p < 0.05; ** p < 0.01; ***p < 0.001.