Which of the following is NOT a characteristic of a randomized control trial?

The correct answer is that allowing for subjective bias in participant selection is not a characteristic of a randomized control trial (RCT). In a well-conducted RCT, participants are randomly assigned to different groups, which helps to eliminate selection bias. The randomness in assignment ensures that any differences between the groups can be attributed to the intervention being tested rather than pre-existing differences among participants.

Furthermore, an RCT measures the effect of an intervention on an outcome in a controlled manner, helping to establish causal relationships. This meticulous design is one of the primary strengths of RCTs, as it enables researchers to draw more reliable conclusions about the efficacy of an intervention without the confounding factors that may affect the outcomes in non-randomized studies. Therefore, the randomness in participant selection is a fundamental component of RCTs, making subjective bias counterproductive to the trial's purpose and integrity.