Table 1 Characteristics of study participants by household, stratified by study wave
|  | Total (N = 1967 households) | Wave 1 (N = 612 households) | Wave 2 (N = 716 households) | Wave 3 (N = 639 households) |
|---|---|---|---|---|
Number of household members | ||||
 Mean (SD) | 3.77 (1.07) | 3.71 (0.979) | 3.82 (1.08) | 3.77 (1.13) |
 Median [Min, Max] | 4.00 [2. 7] | 4.00 [2.00, 6.00] | 4.00 [2.00, 6.00] | 4 [2. 7] |
| Â | N (%) | N (%) | N (%) | N (%) |
County | ||||
 Alameda | 529 (26.9) | 218 (35.6) | 167 (23.3) | 144 (22.5) |
 Contra Costa | 298 (15.1) | 121 (19.8) | 81 (11.3) | 96 (15.0) |
 Marin | 22 (1.1) | 4 (0.7) | 11 (1.5) | 7 (1.1) |
 Napa | 14 (0.7) | 5 (0.8) | 3 (0.4) | 6 (0.9) |
 San Francisco | 388 (19.7) | 69 (11.3) | 146 (20.4) | 173 (27.1) |
 San Mateo | 153 (7.8) | 42 (6.9) | 69 (9.6) | 42 (6.6) |
 Santa Clara | 411 (20.9) | 108 (17.6) | 173 (27.1) | 130 (20.3) |
 Solano | 68 (3.5) | 22 (3.6) | 32 (4.5) | 14 (2.2) |
 Sonoma | 84 (4.3) | 23 (3.8) | 34 (4.7) | 27 (4.2) |
Race | ||||
 White Alone | 1098 (55.8) | 341 (55.7) | 413 (57.7) | 344 (53.8) |
 Black or African American Alone | 147 (7.5) | 56 (9.2) | 45 (6.3) | 46 (7.2) |
 Asian alone | 510 (25.9) | 159 (26.0) | 171 (23.9) | 180 (28.2) |
 American Indian or Alaskan Native | 13 (0.7) | 4 (0.7) | 3 (0.4) | 6 (0.9) |
 Native Hawaiian or Pacific Islander alone | 5 (0.3) | 2 (0.3) | 2 (0.3) | 1 (0.2) |
 Some other race alone | 103 (5.2) | 23 (3.8) | 44 (6.1) | 36 (5.6) |
 Two or more races | 91 (4.6) | 27 (4.4) | 38 (5.3) | 26 (4.1) |
Hispanic | ||||
 Non-Hispanic household | 1578 (80.2) | 496 (81.0) | 582 (81.3) | 500 (78.2) |
 Hispanic household | 389 (19.8) | 116 (19.0) | 134 (18.7) | 139 (21.8) |
Household income | ||||
 Less than $19,999 | 110 (5.6) | 34 (5.6) | 40 (5.6) | 36 (5.6) |
 $20,000 to $39,999 | 158 (8.0) | 51 (8.3) | 54 (7.5) | 53 (8.3) |
 $40,000 to $59,999 | 188 (9.6) | 53 (8.7) | 71 (9.9) | 64 (10.0) |
 $60,000 to $79,999 | 205 (10.4) | 61 (10.0) | 75 (10.5) | 69 (10.8) |
 $80,000 to $99,999 | 205 (10.4) | 58 (9.5) | 72 (10.1) | 75 (11.7) |
 $100,000 to $149,999 | 394 (20.0) | 107 (17.5) | 140 (19.6) | 147 (23.0) |
 $150,000 or more | 707 (35.9) | 248 (40.5) | 264 (36.9) | 195 (30.5) |
Multi-parent household | ||||
 Yes | 1772 (90.1) | 555 (90.7) | 655 (91.5) | 562 (87.9) |
 No | 195 (9.9) | 57 (9.3) | 61 (88.5) | 77 (12.1) |
Weekday of reported contacts | ||||
 Weekday | 1611 (81.9) | 510 (83.3) | 615 (85.9) | 486 (76.1) |
 Weekend | 356 (18.1) | 102 (16.7) | 101 (14.1) | 153 (23.9) |
Work from home1 | ||||
 Adults work from home | 1039 (54.9) | 437 (74.2) | 329 (48.0) | 273 (44.3) |
 Adults do not work from home | 852 (45.1) | 152 (25.8) | 357 (52.1) | 343 (55.7) |