A reflexochirosteopathic clinic performs a study to demonstrate the effectiveness of their treatment for back pain. They recruit 50 patients. After a month, ten remain. All ten report some improvement in their condition, which is hailed by the clinic as validating the efficacy of their treatment. Which of the following factors might be influencing these results?
A) Placebo effect (remaining participants' belief that the treatment has worked has affected their ratings of its effectiveness)
B) Differential mortality (participants for whom the treatment didn't work dropped out of the study)
C) Regression to the mean (participants joined the study when their pain was at its worst, and so it is likely to have decreased anyway)
D) All of these

Question

Quizplus · Accepted Answer

All three factors could be influencing the results. The placebo effect could be at play, as those who remained may have had a belief that the treatment would work and reported improvement despite the treatment not being effective. Differential mortality could have also influenced the results, as those who did not experience improvement may have dropped out of the study, leaving only those who did experience improvement. Finally, regression to the mean could have played a role, as those who joined the study when their pain was at its worst may have experienced a natural decrease in pain over time regardless of the treatment they received.

A Reflexochirosteopathic Clinic Performs a Study to Demonstrate the Effectiveness