Table 2.
Sample sizes by site for each data type
| Measurements | Birmingham, AL | Chicago, IL | Minneapolis, MN | Oakland, CA |
|---|---|---|---|---|
| Morningness–Eveningness Questionnaire (MEQ) | 551 | 419 | 603 | 627 |
| Cambridge–Hopkins Restless Legs Questionnaire (RLS) | 601 | 449 | 689 | 663 |
| Household sleep environment | 596 | 446 | 688 | 677 |
| Wrist actigraphy | ||||
| Files received | 193 | 311 | 274 | 183 |
| Valid files | 171 (89%) | 286 (92%) | 268 (98%) | 174 (95%) |
| Home Sleep Test | ||||
| Files received | 140 | 219 | 205 | 156 |
| Valid files | 125 (89%) | 185 (84%) | 184 (90%) | 125 (80%) |
| Pittsburgh Sleep Quality Index (PSQ) | 211 | 351 | 268 | 329 |
| Epworth Sleepiness Scale (ESS) | 222 | 354 | 274 | 362 |
| Insomnia Severity Index (ISI) | 224 | 353 | 275 | 360 |
| HOBO (light, temperature) | 150 | 229 | n/a | n/a |
| Extech (sound) | 146 | 208 | n/a | n/a |