Table 1.

Tool for assessing risk of bias.

Domain	Criteria for low risk of bias rating	Examples of factors considered in assessment
Sequence generation	Study authors reported the use of a random component in the sequence generation process.	Use of a random component, such as a random number table or computer random number generation; statement by study author that animals were randomly allocated.
Allocation concealment	Study authors reported that study personnel could not foresee which animals were allocated to the various experimental groups.	Use of sequentially numbered cages or animals.
Blinding	Study authors reported that personnel and outcome assessors were adequately prevented from knowledge of the allocated exposures during the study.	Use of masked identifiers in the study and for outcome assessment.
Incomplete outcome data	Study authors reported when and why participants left the study.	The number of animals allocated to experimental groups was reported and/or adequate follow up of dams and offspring (for mammalian studies) was carried out; the number of organisms allocated to experimental groups was reported and/or organisms were adequately followed up after exposure (for non­mammalian studies).
Selective reporting	The study’s prespecified outcomes that are of interest in the review were reported in a prespecified way.	The number of animals or organisms analyzed for outcomes of interest was reported, or study authors provided additional data; study methods matched study results for outcomes of interest.
Conflict of interest	The study was free of support from a company, study author, or other entity having a financial interest in the exposures of interest in the review.	The study was funded or conducted by companies with a financial interest in PFOA; companies provided services to assist in the completion of the study, evaluate the data, or write the manuscript; or the publication or report included a declaration of conflicts of interest.
Other bias	Study appears to be free of other sources of bias.	Other potential sources of bias related to the specific study design.