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Clinical Trial Summary

The post-hoc fallacy (also termed the post-hoc-ergo-propter-hoc fallacy) has been recognized for centuries with endless relevance. The general concept in medical care is that patients who improve after a treatment are not necessary patients who improve because of a treatment. Modern medicine provides multiple opportunities to examine such pitfalls of judgment due to the prevailing uncertainty, incompleteness of our understanding pathogenic mechanisms, and natural tendency to connect treatments to outcomes. In this study, we will investigate whether judgments about vitamin supplementation might demonstrate the post-hoc fallacy.


Clinical Trial Description

We plan to conduct a brief survey of pharmacies portraying a patient in two slightly different versions. One version will portray the patient who feels better after starting a vitamin supplement whereas another version will portray the patient who feels unchanged after starting a vitamin supplement. The patients will be randomly assigned to participants and otherwise contain identical information. Judgments will be measured by eliciting participants recommendation about continuing the vitamin (Appendix_Script). ;


Study Design


Related Conditions & MeSH terms


NCT number NCT05686889
Study type Interventional
Source Sunnybrook Health Sciences Centre
Contact Donald A Redelmeier, MD, MSc
Phone 4164806999
Email dar@ices.on.ca
Status Not yet recruiting
Phase N/A
Start date May 1, 2023
Completion date September 1, 2028

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