Certified Clinical Research Coordinator (CCRC) Practice Exam

Which type of blindness refers to the subject being unaware of their treatment assignment?

1. Single Blind

2. Double Blind

3. Triple Blind

4. Open Label

The correct answer is: Single Blind

The term single blind refers to a study design in which only one party involved in the trial remains unaware of the treatment assignment, typically the participant. This design is employed to prevent bias in participants' responses or behavior based on their knowledge of group allocation. For instance, if participants are unaware of whether they are receiving the active treatment or a placebo, their outcomes may be more objective and less influenced by expectations. In contrast, double blind studies involve both participants and researchers being kept unaware of treatment assignments, thereby minimizing bias from both sides. Triple blind studies extend this further by including another level of blinding, often regarding the data analysis team as well. Open label studies, on the other hand, have no blinding; both the participants and researchers know the treatment being administered, which can introduce biases and affect study outcomes. Therefore, the correct identification of single blind reflects the scenario where subjects do not know their treatment assignment, allowing for a less biased evaluation of treatments.