The BEES-C instrument can be used: (i) as an instrument by researchers evaluating their

proposed study design to ensure that the study quality is maximized; (ii) by reviewers of manuscripts and publications to systematically assess the quality of the research and identifying areas where quality could be improved; (iii) by those performing systematic reviews for evaluating study quality in order to inform decision-making (e.g., Is a study of sufficiently high quality to use in developing regulatory standards? Should a study be included in a meta-analysis?); and (iv) by others wishing to incorporate BEES-C into their currently existing review schemes. For example, many of the issues in our proposed approach that are specifically applicable to short-lived chemicals are not yet part of the draft Office of Health Assessment and Translation Approach SRT1720 cost (NTP,

2013) but could be PARP inhibitor incorporated into their approach for conducting “literature-based evaluations to assess the evidence that environmental chemicals, physical substances, or mixtures (collectively referred to as “substances”) cause adverse health effects. Implicit in this study quality evaluative instrument is that the manuscript or proposal will explicitly report on each of the issues below. In other words, in order to assess whether the study meets the criteria for a given tier, the information on that issue must be clearly described. For studies relying on previously-published biomonitoring data (e.g., US National Health and Nutrition Examination Survey [NHANES]), the same reporting requirements must be met. Authors should be explicit in their description of methods, including pertinent details such as limit of detection for the study, relative standard deviation and relevant quality control

parameters. The lack of numeric scoring for this process is intentional. There will no doubt be instances where a study is of high quality for most components, but has not addressed a key issue that substantially reduces confidence in the study results. much An overall high “score” would mask this problem. Instead, we propose a qualitative approach that increases flexibility. A final note: We are unaware of studies that would be categorized as Tier 1 for all aspects of the evaluation. While a study that falls into Tier 1 for all aspects is certainly a goal and would provide robust data, it is the case that most studies will contain aspects that would be considered Tier 2 or 3. Depending on the users’ intent for the study data, this may not be problematic for certain evaluative issues. On the other hand, there are some issues for which a Tier 3 designation would render the study of low utility (e.g., inability to demonstrate samples were free of contamination). We first describe BEES-C components specifically related to short-lived biomarkers. This is followed by aspects of BEES-C that pertain to more general epidemiological study design issues.