Rated quality of reviewed studies
| Rona et al 14 | Mansfield et al 24 | McCarroll et al 25 | Hotopf et al 20 | Adler et al 22 | Ames et al 23 | Grieger et al 21 | Steel-Fisher et al 26 | Chaudhury et al 27 | |
| Type of study | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
| Sampling method | 2 | 1 | 2 | 2 | 2 | 2 | 1 | 2 | 1 |
| Aimed to assess tour length | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
| Prospective | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| Appropriate control group | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 |
| Method of health outcome assessment | 2 | 3 | 2 | 2 | 2 | 2 | 2 | 1 | 2 |
| Sample size | 2 | 3 | 3 | 2 | 1 | 1 | 0 | 0 | 0 |
| Response rate greater than 60% | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| Adjusted for confounders of tour length | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| Appropriate statistical tests used | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Conclusions substantiated by results | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| Quality Score | 15 | 15 | 15 | 14 | 12 | 12 | 11 | 10 | 8 |
| Overall quality in relation to tour length | Very High | Very High | Very High | High | High | High | Moderate | Moderate | Low |