The purpose of this study is to evaluate the validity of the standard approach in expert judgment for evaluating precision medicines, in which experts are required to estimate outcomes as if they did not have access to diagnostic information, whereas in fact, they do.

Fourteen clinicians participated in an expert judgment task to estimate the cost and medical outcomes of the use of exome sequencing in pediatric patients with intractable epilepsy in Thailand. Experts were randomly assigned to either an “unblind” or “blind” group; the former was provided with the exome sequencing results for each patient case prior to the judgment task, whereas the latter was not provided with the exome sequencing results. Both groups were asked to estimate the outcomes for the counterfactual scenario, in which patients had not been tested by exome sequencing.

Our study did not show significant results, possibly due to the small sample size of both participants and case studies.

A comparison of the unblind and blind approach did not show conclusive evidence that there is a difference in outcomes. However, until further evidence suggests otherwise, we recommend the blind approach as preferable when using expert judgment to evaluate precision medicines because this approach is more representative of the counterfactual scenario than the unblind approach.

Hindsight bias means knowing the outcome may profoundly influence the perception of past events and prevent a realistic appraisal of what actually occurred.

To evaluate the role of hindsight bias on psychiatrists' diagnosis.

A psychiatric vignette was made, and validated by expert psychiatrists in national board of psychiatry. They defined the most probable (Bipolar Mood Disorder) and the least probable diagnosis (Schizoaffective disorder). We designed three types of questionnaire, Type A: the basic vignette with an additional explain that in pervious admission the diagnosis was Schizoaffective disorder, Type B: the basic vignette with a suggestion of Bipolar mood disorder, and Type C: the basic vignette without any suggestion. These three forms were sent out to psychiatrists by randomization and concealment allocation in three groups to evaluate their diagnosis.

Of the 240 psychiatrists included,173 persons responded (response rate 72%).There were 52 persons in group A with Schizoaffective disorder suggestion, 63 in group B with Bipolar mood disorder suggestion and 58 in the control group. There was a significant increase of schizoaffective disorder diagnosis (Pv <0.001) but there was not a significant difference for Bipolar Mood Disorder or any other diagnoses. There was no difference in mean age, sex and duration of clinical practice between groups.

According to this study decision-making in psychiatry may be vulnerable to biases like hindsight bias. Insight via education appears the major means to avoid distorting decision-making processes.