Testimonials
The Problems with Testimonials "For centuries doctors used leeches and lancets to relieve patients of their blood. They KNEW bloodletting worked. EVERYBODY said it did. When you had a fever and the doctor bled you, you got better. EVERYONE knew of a friend or relative who had been at death’s door until bloodletting cured him. Doctors could recount thousands of successful cases." You can't tell in an individual case what would have happened if nothing was done, or something else - particularly for a condition that has a variable clinical course. For example, most people with COVID survive; and many people with indolent cancers will live without ever needing treatment. So like the blood-letting example they cannot assert that what they did mattered - or if they would have done well anyway. - Testimonials can't inform about the number of persons who have used the intervention and did not benefit or were harmed. - Testimonials provide no denominator - the number of