Table.
GRADE Evaluation of interventions for Head lice.
| Important outcomes | Eradication rate | ||||||||
| Studies (Participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| What are the effects of physically acting treatments for head lice? | |||||||||
| 1 (73) | Eradication rate | Dimeticone versus malathion | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 2 (235) | Eradication rate | Dimeticone versus permethrin | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for early termination of one of the RCTs at 9 days |
| 1 (216) | Eradication rate | Herbal and essential oils versus malathion | 4 | –1 | 0 | –1 | 0 | Low | Quality point deduced for weak methods (all of the authors were employees of the pharmaceutical company that funded the trial); directness point deducted for unclear generalisability of the single specific essential oil |
| 1 (45) | Eradication rate | Herbal and essential oils versus permethrin | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for sparse data; directness point deducted for unclear generalisability of the single specific essential oil |
| 1 (123) | Eradication rate | Herbal and essential oils versus pyrethrum | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for sparse data; directness point deducted for unclear generalisability of the single specific essential oil |
| 1 (216) | Eradication rate | Isopropyl myristate versus malathion | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for weak methods (published author information includes the name of a pharmaceutical company that is also the name next to the isopropyl myristate-containing intervention used in the trial); directness point deducted due to intervention containing various other chemicals |
| 1 (168) | Eradication rate | Isopropyl myristate versus permethrin | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for sparse data; directness point deducted for early termination of 1 RCT |
| 1 (60) | Eradication rate | Isopropyl myristate versus pyrethrum | 4 | –2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data and incomplete reporting of results |
We initially allocate 4 points to evidence from RCTs, and 2 points to evidence from observational studies. To attain the final GRADE score for a given comparison, points are deducted or added from this initial score based on preset criteria relating to the categories of quality, directness, consistency, and effect size. Quality: based on issues affecting methodological rigour (e.g., incomplete reporting of results, quasi-randomisation, sparse data [<200 people in the analysis]). Consistency: based on similarity of results across studies. Directness: based on generalisability of population or outcomes. Effect size: based on magnitude of effect as measured by statistics such as relative risk, odds ratio, or hazard ratio.