On one hand, misery loves company. On the other, it is not particularly comforting to know that there is little evidence supporting medical recommendations. An excerpt provided at Overcoming Bias (orginal is behind a paywall):
Level of evidence provides the link between recommendations and
evidence base. Although there is significant variation among individual
guidelines in available evidence supporting recommendations, the
median of level of evidence A recommendations [i.e., those supported by
more than one randomized trial] is only 11% across current guidelines,
whereas the most common grade assigned is level of evidence C,
indicating little to no objective empirical evidence for the
recommended action. . . . Interestingly, our findings are
reflective of a specialty — cardiology — that has a large pool of
research to draw on for its care recommendations. Guidelines
in other medical areas in which large clinical trials are performed
less frequently may have an even weaker evidence-based foundation.
evidence base. Although there is significant variation among individual
guidelines in available evidence supporting recommendations, the
median of level of evidence A recommendations [i.e., those supported by
more than one randomized trial] is only 11% across current guidelines,
whereas the most common grade assigned is level of evidence C,
indicating little to no objective empirical evidence for the
recommended action. . . . Interestingly, our findings are
reflective of a specialty — cardiology — that has a large pool of
research to draw on for its care recommendations. Guidelines
in other medical areas in which large clinical trials are performed
less frequently may have an even weaker evidence-based foundation.
Further reading on this problem:
http://spiresecurity.typepad.com/spire_security_viewpoint/2006/05/i_am_so_glad_th.html