> In fact, the results were actually quite good for the people in the study who got the colonoscopies — a 31% reduction in colon cancer risk and a 50% reduction in risk of dying from it, experts said.

> “In order for a colonoscopy to be effective, you have to have it done,” said Dr. Robin Mendelsohn

Huh? So the study found that being randomly selected to be invited for a colonoscopy doesn't improve your risk of dying from colon cancer, but if you bother to get the colonoscopy, it reduces risk by 50%? Maybe they previously though it would decrease risk by more than 50%.