Craig
Levels of evidence have to do with the validity or
quality of the evidence - that is, how "good" is the
information? is it "high quality" or valid?
Generalisability has to do with whether that evidence,
good or bad, can be applied to my population. See for
example the Oxford CEBM at:
http://www.cebm.net/levels_of_evidence.asp
(a quote from their page: "...these levels and grades
speak only to the VALIDITY of evidence about
prevention, diagnosis, prognosis, therapy, and harm.
Other strategies, described elsewhere in the Centre’s
pages, must be applied to the evidence in order to
generate clinically useful measures of its POTENTIAL
CLINICAL APPLICATIONS and to incorporate vital
patient-values into the ultimate decisions." emphasis
mine)
Also:
http://www.aafp.org/afp/20040201/548.html
Bill C
--- Craig Lockwood <[log in to unmask]>
wrote:
> Dear List,
>
> With regard to levels of evidence, I am interested
> in your views, and how
> they are being applied, particularly within
> systematic reviews. I was
> interested to recently hear someone state that
> levels of evidence are łabout
> generalisability˛, while I have considered them to
> relate to study design,
> rather than either internal or external validity. My
> view has been that
> while an RCT is categorised as high level evidence,
> a poor quality RCT would
> not have the same generalisability as a high quality
> RCT, yet both would be
> classified as high level evidence on face value of
> study design, thus level
> of evidence does not consitute a accurate measure of
> generalisability.
> (please feel free to offer comment on my thought
> processes)
>
> Within reviews, I use levels of evidence as one of
> several methods of
> indicating study design, other tools assist in
> evaluating quality which has
> more of an impact on potential generalisability than
> the level of evidence.
> Can I ask for others points of view please.
>
> Regards
> Craig
>
=====
Bill Cayley, Jr, MD MDiv [log in to unmask]
Augusta Family Medicine Home Address
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