Table 1.
Domains of risk of bias in RoB-SPEO.
| Domain | Description of bias | |
|---|---|---|
| 1 | Bias in selection of participants into the study | Bias in selection of participants into the study (commonly called selection bias) is the bias due to systematic differences between the characteristics of the study sample (defined as the sample of individuals participating in the study) and those of the target population (defined as the population for which the authors of the study sought to assess exposure) (Porta, 2014). |
| 2 | Bias due to lack of blinding of study personnel | Bias due to a lack of blinding of study personnel (commonly called performance bias) is the bias that arises when there is a lack of blinding of exposure assessors and other study personnel to relevant participant characteristics (e.g. disease status) that leads to exposure assessment that differs depending on participant characteristics. |
| 3 | Bias due to exposure misclassification | Bias due to exposure misclassification is “erroneous [and systematic] classification of an individual, a value, or an attribute into a [exposure] category other than that to which it should be assigned”, leading to under- or over-estimation of prevalence of exposure status (or level) (Porta, 2014). |
| 4 | Bias due to incomplete exposure data | Bias due to incomplete exposure data is the bias that arise from exposure data missing in a way that the exposure assessment is differential by exposure status (or level) in the target population (i.e., not random). |
| 5 | Bias due to selective reporting of exposures | Bias due to selective exposure reporting is the systematic difference arising from selective reporting (under- or over-reporting) of exposures or exposure categories. |
| 6 | Bias due to conflict of interest | Bias due to conflicts of interest is the bias introduced if financial and other interests influence the design, conduct, data collection, analysis and/or reporting of a study (Woodruff and Sutton, 2014). |
| 7 | Bias due to differences in numerator and denominator | Bias due to differences in numerator and denominator is the bias that arises when there is a mismatch of definition and/or counting of persons contributing to the numerator and the denominator in the ratio used to estimate prevalence (Williams, Najman and Clavarino, 2006). |
| 8 | Other bias | Other bias is any other bias specific to a particular study rather than applicable to all studies. |
Source:Pega et al., 2020b.