Good Clinical Practice (GCP) Practice Exam

What is double-blinding in a clinical trial?

1. Only the subjects remain unaware of their treatment

2. Both subjects and investigator(s) are unaware of treatment assignments

3. Everyone involved, including data analysts, is aware of the treatment

4. Only the monitor is unaware of the treatments

The correct answer is: Both subjects and investigator(s) are unaware of treatment assignments

Double-blinding is a key principle in clinical trials designed to minimize bias. When both the subjects participating in the study and the investigator(s) administering the treatment are unaware of the treatment assignments, this approach helps ensure that neither party's expectations or beliefs influence the outcomes or the assessment of the treatment's effects. In a double-blinded study, the subjects do not know whether they are receiving the experimental treatment or a placebo, which helps prevent any psychological effects from influencing their responses. Simultaneously, the investigators are kept in the dark about which treatment each subject is receiving, preventing any biases in how they interact with or assess the participants. This method enhances the credibility of the trial results and helps to ensure that any observed effects can be attributed to the treatment itself rather than external factors. The other choices fail to encompass the essence of double-blinding. If only the subjects were unaware of their treatment, it could lead to biased results, as investigators might unintentionally influence the subjects based on their knowledge. Similarly, if all parties, including data analysts, are aware of the treatment assignments, the risk of bias is heightened. Lastly, if only the monitor is unaware, it does not adequately protect against biases that could arise from the subjects or investigators being aware