“Effectiveness” is at the forefront of the health policy debate. Effectiveness is the assessment of whether any particular medical intervention actually advantages patients when prescribed in practice settings. To be considered effective, the intervention must result in a clinically meaningful improvement for an adequate percentage of patients. Furthermore, it must not result in a clinically important adverse outcome in too many. Clearly, “effectiveness” is a value-laden construct. How is “meaningful improvement” defined and by whom? How is “important adverse outcome” defined and by whom? How are “adequate percentage” and “too many” defined and by whom?

“Cost-effectiveness” is even more value-laden. It is legislated to be off-the-table in the machinations of the Affordable Care Act for reasons that vary from fear of rationing to fear of compromising profit margins. But no one can exclude cost-effectiveness from the patient-doctor dialogue. Considerations of co-pays and deductibles often weigh heavily in the valuation of interventions.

The greatest advance in clinical medicine in my time in the practice, fast approaching 50 years, is that today patients and their doctors can assess effectiveness as collaborators. No longer does an imperious pronouncement by a physician suffice. Rather, the patient should occupy the driver’s seat with the physician as navigator. For each option in intervention, the patient asks, “Based on the available science, what is the best I can expect?”

For nearly 50 years, no prescription drug could be marketed unless the FDA was convinced that it had a tolerable benefit-to-risk ratio based on scientific studies. The bar for devices (like hip replacements) and procedures (like liposuction) is not as high, but there is usually some informative clinical science of this nature. The science is generally designed in the hope of demonstrating a favorable benefit-to-risk ration. Hence, patients and interventions are chosen to measure outcomes in the best case. However, make no mistake; neither the fact of FDA approval nor common practice is an adequate response to “What is the best I can expect?” If the best case falls short in your mind, why would you acquiesce to the intervention?

Consider Pill A, which reduces a blood chemical known to predispose to heart damage. The “best case” science says that if 100 adults take the pill for 5 years, perhaps 2 will be spared non-fatal heart damage and 10 will suffer muscle pain. However there is no suggestion that anyone will be spared death before their time. Would you take Pill A? Even if it was free? Consider Pill B, which reduces a blood chemical associated with damage in many body organs and with death before one’s time. Scientific studies of Pill B, some lasting a decade, have proved disappointing both in terms of preventing body damage and causing toxicity. But these studies were done on early versions of this category of pharmaceutical. Would you take a new version or a combination of these agents?

Consider Procedures A and B, both designed to overcome pathology in blood vessels that is associated with organ damage. Procedure A is “minimally invasive”, though it has a 1-2% incidence of catastrophic complications. Procedure B is major surgery with a 5-10% incidence of major complications related to the procedure and a 20-30% incidence of a prolonged period of recovery. Again there is a robust scientific literature saying that neither intervention will improve longevity. The literature that either improves symptoms is highly inconsistent. Nonetheless, these procedures are still offered because they are performed differently today than in the older disappointing studies and they are offered only to candidates thought to be particularly appropriate. If you were deemed “appropriate” would you acquiesce to either procedure?

Pill A is a “statin” for high cholesterol. Pill B is an oral hypoglycemic to lower blood sugar in Type 2 diabetes. Procedure A is stenting for plaques in coronary arteries (or elsewhere) and B is bypass grafting. All are plausible, even sensible, even current common sense. All are sanctioned by august professional bodies and all are covered by health insurance. There is no “right or wrong” answer to the question about patients in general acquiescing to these options. But there is a right answer for you.

Many are capable of rendering the best case science transparent; there are even independent groups of scientists devoted to this exercise. And many more are capable of prescribing and performing according to guidelines and standards. But none of these people can come up with the right answer for you.

That’s why you would be advantaged by a physician who wants to support your valuation of the options. That’s the way you’ll find the shoe that fits.