Pre COVID-19 | COVID-19 | |||
---|---|---|---|---|
Coefficient | P value | Coefficient | P value | |
Panel A. Mean equation | ||||
\(\mu_{1}\) | − 0.000 | 0.380 | 0.000 | 0.349 |
\(\emptyset_{11}\) | − 0.171a | 0.000 | − 0.093b | 0.019 |
\(\emptyset_{12}\) | − 0.018 | 0.501 | 0.076c | 0.052 |
\(\emptyset_{13}\) | 0.102c | 0.072 | 0.083 | 0.150 |
\(\mu_{2}\) | − 0.000 | 0.277 | 0.000c | 0.052 |
\(\emptyset_{21}\) | 0.067 a | 0.000 | 0.018 | 0.499 |
\(\emptyset_{22}\) | − 0.081a | 0.000 | − 0.221a | 0.000 |
\(\emptyset_{23}\) | 0.182a | 0.000 | 0.132c | 0.094 |
\(\mu_{3}\) | − 0.000 | 0.323 | 0.000 | 0.249 |
\(\emptyset_{31}\) | 0.017c | 0.071 | 0.015 | 0.509 |
\(\emptyset_{32}\) | 0.026c | 0.052 | 0.043 | 0.223 |
\(\emptyset_{33}\) | − 0.225a | 0.000 | − 0.188a | 0.000 |
Panel B. Variance equation | ||||
\(c_{1}\) | 0.000a | 0.000 | 0.000b | 0.012 |
\(c_{2}\) | 0.001a | 0.000 | 0.001a | 0.000 |
\(c_{3}\) | 0.000a | 0.000 | 0.001a | 0.000 |
\(a_{11}\) | 0.073b | 0.018 | − 0.029c | 0.070 |
\(a_{12}\) | 0.014b | 0.019 | 0.042a | 0.000 |
\(a_{13}\) | 0.027a | 0.000 | − 0.002c | 0.055 |
\(a_{21}\) | 0.011c | 0.068 | 0.061a | 0.000 |
\(a_{22}\) | 0.045a | 0.000 | 0.150a | 0.000 |
\(a_{23}\) | 0.060a | 0.000 | 0.015c | 0.061 |
\(a_{31}\) | 0.002 | 0.293 | − 0.065a | 0.000 |
\(a_{32}\) | 0.117a | 0.001 | 0.083a | 0.000 |
\(a_{33}\) | 0.181a | 0.000 | 0.063a | 0.000 |
\(b_{11}\) | 0.880a | 0.000 | 0.995a | 0.000 |
\(b_{12}\) | − 0.144a | 0.000 | 0.037a | 0.000 |
\(b_{13}\) | − 0.129a | 0.000 | 0.025b | 0.040 |
\(b_{21}\) | − 0.058b | 0.032 | − 0.035c | 0.052 |
\(b_{22}\) | 1.256a | 0.000 | 0.874a | 0.000 |
\(b_{23}\) | − 0.269a | 0.000 | − 0.019c | 0.094 |
\(b_{31}\) | − 0.153 | 0.113 | 0.027c | 0.079 |
\(b_{32}\) | 1.028a | 0.000 | 0.069a | 0.000 |
\(b_{33}\) | 0.860a | 0.000 | 0.938a | 0.000 |
\(d_{1}\) | − 0.035b | 0.043 | 0.041b | 0.018 |
\(d_{2}\) | − 0.016c | 0.061 | 0.047a | 0.001 |
\(d_{3}\) | − 0.017c | 0.082 | 0.034a | 0.006 |
Panel C: Constant correlations | ||||
\(p_{21}\) | 0.783a | 0.000 | 0.860a | 0.000 |
\(p_{31}\) | 0.644a | 0.000 | 0.802a | 0.000 |
\(p_{32}\) | 0.691a | 0.000 | 0.831a | 0.000 |
Panel D: Robustness tests | ||||
Log L | 11,912.2 | 24,025.6 | ||
AIC | − 20.972 | − 20.392 | ||
SIC | − 20.850 | − 19.918 | ||
\(Q_{1}\)(20) | 42.173a | 0.003 | 36.776b | 0.012 |
\(Q_{2}\)(20) | 45.954a | 0.000 | 36.444b | 0.013 |
\(Q_{3}\)(20) | 22.238 | 0.245 | 25.542 | 0.181 |
\(Q_{1}^{2}\)(20) | 2.610 | 0.991 | 18.776 | 0.352 |
\(Q_{2}^{2}\)(20) | 4.859 | 0.988 | 14.444 | 0.415 |
\(Q_{3}^{2}\)(20) | 5.166 | 0.981 | 10.542 | 0.480 |