Methodological characteristics of data-based studies included in review (N=131)
| n (%) | |
|---|---|
| Method | |
| Quantitative | 107 (81.7) |
| Qualitative | 22 (16.1) |
| Mixed methods (quantitative and qualitative) | 2 (1.5) |
| Design | |
| Analysis of text or visual materials | 9 (6.9) |
| Key informants | 2 (1.5) |
| Focus groups | 6 (4.6) |
| Other qualitative design | 5 (3.8) |
| Cross-sectional survey | 100 (76.3) |
| Prospective survey | 6 (4.6) |
| Experimental design | 1 (0.8) |
| Other quantitative design | 1 (0.8) |
| Sampling methodology* | |
| Convenience sample assessed | 50 (38.2) |
| Entire population or a random sample assessed | 73 (55.7) |
| Archival data assessed | 9 (6.9) |
| Sampling frame | |
| Educational institution | 75 (57.3) |
| Café/restaurant | 8 (6.1) |
| Local community, including health clinics | 19 (14.5) |
| National | 5 (3.8) |
| Multiple frames | 15 (11.5) |
| Archival data | 9 (6.9) |
| Representativeness of human samples (n=111) | |
| Not representative | 47 (35.9) |
| Representative of the population of a city, state or region | 10 (7.6) |
| Representative of the population of a nation | 4 (3.1) |
| Representative of a school system or educational institution | 53 (40.5) |
| Representative of waterpipe customers in a retail establishment | 4 (3.1) |
| Representative of other populations | 5 (3.8) |
*Numbers total >131 due to some studies having multiple samples and/or frames.