ROBVALU: a tool for assessing risk of bias in studies about people's values, utilities, or importance of health outcomes.

People’s values are an important driver in healthcare decision making. The certainty of an intervention’s effect on benefits and harms relies on two factors: the certainty in the measured effect on an outcome in terms of risk difference and the certainty in its value, also known as utility or importance. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) working group has proposed a set of questions to assess the risk of bias in a body of evidence from studies investigating how people value outcomes. However, these questions do not address risk of bias in individual studies that, similar to risk-of-bias tools for other research studies, is required to evaluate such evidence. Thus, the Risk of Bias in studies of Values and Utilities (ROBVALU) tool was developed. ROBVALU has good psychometric properties and will be useful when assessing individual studies in measuring values, utilities, or the importance of outcomes. As such, ROBVALU can be used to assess risk of bias in studies included in systematic reviews and health guidelines. It also can support health research assessments, where the risk of bias of input variables determines the certainty in model outputs. These assessments include, for example, decision analysis and cost utility or cost effectiveness analysis for health technology assessment, health policy, and reimbursement decision making.