The word diagnosis derives from the Latin 'di' which means two, and 'agnosis' which means without knowledge. So, you can say a diagnosis is a meeting of two minds that don't have a clue as to what's going on - not very reassuring if it's a group of doctors trying to figure out what's wrong with you!
A recent study in the Journal of the American Medical Association (JAMA) revealed some rather shocking numbers about physicians’ diagnostic accuracy and confidence (1). Turns out the 118 MDs who participated in the study were right only 55% of the time on easy cases and just 6% on the tough ones. Even more surprising, an earlier Pew Survey (2) showed that patients were 41% accurate in their own self-diagnosis from on-line resources, giving them a statistical advantage over their more 'learned' MD counterparts.
So, the question is, do we truly have a 'health crisis' in this country, or is it just an 'OVER diagnosis' problem - a system filled with people lead to believe they have pressing health issues when in fact they don't? When it comes to knowing what ails you, two heads aren't necessarily better than one. Maybe it's smarter to just trust the REAL doctor inside you.
(1) JAMA - Physicians’ Diagnostic Accuracy, Confidence, and Resource Requests Nov 2013, Meyer et al
(2) Pew Research Internet Project - Health Online 2013, Fox et al