2. 'due weight' implicitly acknowledges that there are many factors that contribute to decisions about the care of patients. There are many factors other than the results of randomised controlled trials that may weigh heavily in both clinical and policy decisions (for instance, patient preferences and resources). This definition requires that valid, relevant evidence should be considered alongside other relevant factors in the decision making process. It does not assume that any one sort of evidence should necessarily be the determining factor in a decision.