Agreed with most here.
"No RCT = no evidence" is not part of the philosophy of EBM.
A systematic review is a study design, so I do not understand what is meant
by "EBM in the sense of systematic reviews" (like, what is EBM in the sense
of case-control studies?). Of note systematic reviews and meta-analyses
have a very rich of summarizing observational studies (to begin with its
origins in agriculture, education, and psychology).
That Cochrane limited its scope to issues that could be summarized by
looking exclusively at RCTs appears to be more out of methodological and
practical convenience appropriate to its early history. As other questions
need to be addressed, the Collaboration is moving forward wtih its interest
in incorporating other study designs (non-RCTs, qualitative research,
According to the hierarchy of evidence, almost never will you be in a
situation where there is no evidence.
> -----Original Message-----
> From: Guthrie, Dr Bruce [SMTP:[log in to unmask]]
> Sent: Friday, August 17, 2001 12:07 PM
> To: [log in to unmask]
> Subject: Re: Randomized versus non-randomized studies
> > I take issue with the definition of evidence-based medicine
> Leaving aside formal definitions, I think you can argue that one
> effect of the evidence based medicine focus on hierarchies of
> evidence is that in some situations for some people, 'no rct' is
> taken to be synonymous with 'no evidence'.
> Cochrane is a major example of this (and David was careful to say
> ebm in the sense of systematic reviews not ebm in the sense of
> clinical practice - although there is another strand of ebm which
> holds up systematic reviews as the ideal thing for clinicians to
> For most of the Cochrane review groups, it isn't actually possible to
> reach any very definite conclusion if there isn't rct evidence, no
> matter what other research has been done (there are exceptions to
> this eg the effective practice group, although they still only allow a
> limited number of methods as 'acceptable', and I'm aware that there
> is a non randomised studies methodology group looking at this).
> It probably is too broad brush to distinguish broad churches like
> ebm and hta like that, but I think David is making an important, real
> distinction between two ways of thinking.
> Bruce Guthrie,
> MRC Training Fellow in Health Services Research,
> Department of General Practice,
> University of Edinburgh,
> 20 West Richmond Street,
> Edinburgh EH8 9DX
> Tel 0131 650 9237
> e-mail [log in to unmask]