Table 3.
Risk of bias assessment for quantitative studies
| External validity domains | Internal validity domains | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| First author year | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | Overall risk |
| Al Mansour 2015 [95] | N | N | N | Y | Y | Y | Y | Y | N/A | Y | Moderate |
| Bensoussan 2004 [73] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Braun 2013 [74] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | N | Low |
| Chaterji 2007 [81] | N | N | N | N | Y | Y | Y | Y | N/A | N | Moderate |
| Cohen 2005 [101] | N | Y | Y | N | Y | Y | Y | Y | N/A | Y | Low |
| Cottingham 2015 [96] | N | N | N | Y | Y | Y | Y | Y | N/A | Y | Moderate |
| Cottingham 2017 [97] | N | N | N | Y | Y | Y | Y | Y | N/A | Y | Moderate |
| Cottingham 2018 [82] | N | N | N | Y | Y | Y | Y | Y | N/A | N | Moderate |
| Dooley 2010 [75] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| El-Olemy 2014 [102] | N | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Emslie 2002 [76] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Evans 2008 [83] | Y | Y | Y | N | Y | Y | N | Y | N/A | N | Low |
| Flatt 2013 [77] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | N | Low |
| Hall 2000 [103] | Y | Y | N | N | Y | Y | Y | Y | N/A | Y | Low |
| Harris 2006 [84] | Y | Y | Y | N | Y | Y | N | Y | N/A | N | Moderate |
| Langworthy 2000 [85] | N | N | N | N | Y | Y | Y | Y | N/A | N | High |
| Lin (Section 5, McCabe) 2005 [52] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Lin (Section 6, McCabe) 2005 [52] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Livingston 2010 [86] | Y | Y | Y | N | Y | Y | Y | Y | N/A | N | Moderate |
| Montbriand 2000 [87] | N | N | Y | N | Y | Y | Y | Y | N/A | N | Moderate |
| Morin 2017 [88] | Y | Y | Y | N | Y | Y | Y | Y | N/A | N | Moderate |
| Parker 2013 [78] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Poreddi 2016 [104] | Y | N | Y | Y | Y | Y | Y | Y | N/A | Y | Low |
| Poynton 2006 [98] | Y | Y | N | N | Y | Y | Y | Y | N/A | Y | Moderate |
| Price 2004 [89] | Y | Y | Y | N | Y | Y | N | Y | N/A | N | Moderate |
| Semple 2006 [90] | Y | Y | Y | N | Y | Y | Y | Y | N/A | N | Moderate |
| Taylor 2003 [91] | N | N | N | N | Y | Y | N | Y | N/A | N | High |
| Tiralongo 2010 [99] | Y | Y | Y | N | Y | Y | Y | N | N/A | Y | Moderate |
| Tsai 2008 [92] | N | N | N | N | Y | Y | Y | Y | N/A | N | High |
| Xue 2005 [93] | Y | Y | Y | N | Y | Y | N | Y | N/A | N | Moderate |
| Yu 2015 [100] | N | Y | N | N | Y | Y | Y | N | N/A | Y | Moderate |
| Zhang 2006 [94] | Y | Y | N | Y | Y | Y | Y | Y | N/A | N | Moderate |
| Zhang 2008 [79] | Y | Y | Y | Y | Y | Y | Y | Y | N/A | N | Low |
Domains
1. Was the study’s target population a close representation of the national population in relation to relevant variables?
2. Was the sampling frame a true or close representation of the target population?
3. Was some form of random selection used to select the sample, OR was a census undertaken?
4. Was the likelihood of nonresponse bias minimal?
5. Were data collected directly from the subjects (as opposed to a proxy)?
6. Was an acceptable case definition used in the study?
7. Was the study instrument that measured the parameter of interest shown to have validity and reliability?
8. Was the same mode of data collection used for all subjects?
9. Was the length of the shortest prevalence period for the parameter of interest appropriate?
10. Were the numerator(s) and denominator(s) for the parameter of interest appropriate?
N = criterion not adequately met; Y = criterion adequately met; N/A = criterion not applicable