| Authors | Industry | Country | Morning | Afternoon | Night |
|---|---|---|---|---|---|
| Levin [22] | Paint manuf. | USA | 1.00 | 1.16 | 1.27 |
| Ong [33] | Iron & Steel | Singapore | 1.00 | 0.53 | 0.41 |
| Nag [23] | Textile | India | 1.00 | 0.60 | 0.41 |
| Dembe [19] | NLSY | USA | 1.00 | 1.45 | 1.32 |
| Violanti [27] | Police | USA | 1.00 | 1.22 | 2.17 |
| Average: | All five | 1.00 | 0.94 | 0.85 | |
| USA | Average | 1.00 | 1.31 | 1.30 | |
| Developing | countries | Average | 1.00 | 0.57 | 0.41 |