I too wish everything in medicine was cut and dry. But oftentimes precise numbers are unavailable. More qualitative reasoning such as "high risk," "serious morbidity or mortality" is usually given in medical assessments. Plans are developed based off that assessment. Doctors and patients routinely make well-considered decisions and get consent knowing that exact numbers aren't known. On the other hand, many treatments (pharmaceuticals and screening being 2 major ones) are backed by very reliable studies where numbers are known.
Yet the point is that even when the numbers are absolutely clear cut and are more than relevant to medical decision making, doctors' training doesn't help them reason their way out of a wet paper bag. They're hopeless even when they're provided with a problem that has the equivalent of training wheels and handrails.
