Source of bias | Criteria | Low risk of bias | Medium risk of bias | High risk of bias | Unclear risk of bias |
---|---|---|---|---|---|
Experimental | Is the experiment replicated (at least one replicate; a replicate is not exposed to water in contact with the other replicates) | – Yes | – No – Unknown (assumed to be No) | ||
Exposure | If a solvent is used, is a solvent control present? | – Yes – N/A | – No – Unknown (assumed to be No) | ||
Have effective exposure concentrations been measured? | – Yes | – No – Unknown (assumed to be No) | |||
Selection | Are there differences at baseline between groups C and E? (including difference in exposure environment, difference in biological model, difference in the set of individuals allocated to each group) | – No – N/A (for BA design) | – Yes but the effect is controlled and null – for in situ studies: yes but an attempt to minimize differences is made | – Yes (detail) – Unknown (assumed to be Yes) | |
Performance | Are there differences in the way groups C and E (or B and A) are treated throughout the experiment? | – No | – Yes (detail) – Unknown (assumed to be Yes) | ||
Detection | Are there differences in the way the outcomes of groups C and E (or B and A) are assessed? | – No | – Yes (detail) – Unknown (assumed to be Yes) | ||
Exclusion (or attrition) | Are there differences in the way individuals or observations from groups C and E (or B and A) are removed from the study? | – No | – Yes (detail) – Unknown (assumed to be Yes) | ||
Other | Is there another source of bias? (e.g. reporting bias, insufficient description of the methods, an unforeseen event that occurred during the experiment) | – No | – Yes minor (detail) | – Yes major (detail) |