Table 4.
Model performance for two-, three-, and four-week out-of-sample predictions of the cumulative COVID-19 cases in the top 20 populous states.
| State | Two-week out-of-sample predictions (November 14, 2020) | Three-week out-of-sample predictions (November 21, 2020) | Four-week out-of-sample predictions (November 28, 2020) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Range of predictions | Observed | % Error | Range of predictions | Observed | % Error | Range of predictions | Observed | % Error | |
| California | 964,486–1,017,792 | 990,096 | − 1.1 | 991,330–1,101,984 | 1,053,945 | − 3.3 | 1,021,323–1,211,919 | 1,147,417 | − 7.1 |
| Texas | 927,085–1,044,511 | 984,377 | − 3.0 | 944,996–1,152,937 | 1,050,255 | − 5.0 | 963,036–1,275,089 | 1,128,131 | − 7.6 |
| Florida | 819,518–844,319 | 852,174 | − 2.7 | 836,321–882,500 | 897,322 | − 4.9 | 853,484–927,956 | 953,300 | − 7.7 |
| New York | 515,129–543,158 | 536,214 | − 2.3 | 521,856–573,152 | 568,847 | − 5.6 | 528,035–608,774 | 607,070 | − 9.4 |
| Pennsylvania | 215,722–232,495 | 238,657 | − 7.0 | 223,702–254,648 | 275,513 | − 14.9 | 231,659–281,377 | 321,070 | − 22.7 |
| Illinois | 419,938–459,360 | 511,169 | − 15.2 | 436,352–508,202 | 597,818 | − 23.0 | 452,833–565,200 | 674,072 | − 27.5 |
| Ohio | 221,957–242,352 | 261,483 | − 12.1 | 230,590–267,693 | 305,365 | − 20.1 | 239,068–297,812 | 371,908 | − 30.3 |
| Georgia | 347,637–370,294 | 376,032 | − 5.8 | 351,721–391,865 | 391,429 | − 7.4 | 355,332–416,164 | 408,643 | − 9.3 |
| North Carolina | 278,608–295,263 | 297,973 | − 4.4 | 284,890–314,174 | 316,955 | − 6.9 | 290,521–334,812 | 343,408 | − 11.0 |
| Michigan | 195,442–218,456 | 245,252 | − 16.9 | 204,300–246,177 | 296,840 | − 26.3 | 213,149–279,695 | 347,746 | − 32.4 |
| New Jersey | 245,806–255,510 | 260,430 | − 4.1 | 253,457–271,881 | 285,519 | − 8.7 | 261,572–292,107 | 313,863 | − 13.1 |
| Virginia | 184,386–197,766 | 194,906 | − 3.0 | 187,695–210,732 | 206,751 | − 5.5 | 190,612–224,668 | 223,568 | − 9.9 |
| Washington | 108,774–115,661 | 120,011 | − 7.5 | 110,811–123,182 | 134,118 | − 14.6 | 112,670–131,872 | 151,018 | − 21.9 |
| Arizona | 249,274–255,512 | 263,133 | − 4.3 | 253,739–265,544 | 279,896 | − 7.8 | 258,348–277,724 | 306,868 | − 13.6 |
| Massachusetts | 168,537–179,938 | 180,753 | − 4.9 | 173,406–198,166 | 197,561 | − 9.0 | 178,620–224,517 | 214,874 | − 11.9 |
| Tennessee | 268,495–293,014 | 289,749 | − 4.2 | 279,257–322,714 | 320,729 | − 7.9 | 289,913–356,839 | 345,853 | − 9.0 |
| Indiana | 186,156–203,048 | 222,186 | − 13.3 | 193,852–224,421 | 265,099 | − 22.6 | 201,574–250,066 | 309,503 | − 29.3 |
| Missouri | 190,799–207,726 | 220,768 | − 10.6 | 198,389–228,183 | 253,473 | − 17.3 | 205,381–250,666 | 282,792 | − 21.6 |
| Maryland | 148,742–159,294 | 156,709 | − 2.9 | 151,885–170,824 | 169,804 | − 7.1 | 154,884–184,520 | 185,464 | − 11.8 |
| Wisconsin | 256,093–279,759 | 293,812 | − 9.5 | 275,475–320,478 | 342,155 | − 14.2 | 295,568–369,722 | 386,441 | − 16.1 |