Hello Jon et al;
I agree that there are many many sites of uncertainty; I think of it in the epistemic framework of determinism and indeterminism. There are questions and problems that seem more deterministic (management of metacarpal fractures) and more indeterministic (management of head/neck cancer). One possibility for dealing with this is trying to ascertain which problems are more deterministic and focusing a larger proportion of research monies and data-accrual toward areas where we may have a greater chance of getting better evidence and decreasing the uncertainty. There seems to be a degree of fatalism that surrounds questions of how much we can know and which may be impairing/slowing impetus to accept uncertainty and move forward.
Loree
-----Original Message-----
From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Paul Glasziou
Sent: Monday, August 03, 2009 8:46 AM
To: [log in to unmask]
Subject: Re: Uncertainty
Hi Jon,
Shades of the "unknown unknowns" (attributed to Rumsfled, but also know as the Johari window).
I suspect there are a lot of levels of uncertainty, including at least:
1. Structural uncertainty: where I am not even sure what model/trials to apply.
2. External validity/Appplicability: where I am not sure whether and how
*this* trial (or review) applies
3. Individual uncertainty: of whether the treatment is needed or effective.
E.g, with an NNT of 25, then 24 of the folk either did not need any treatment, or this treatment did not "work".
4. Second order uncertainty: uncertainty about the (known) uncertainty - the CI issue that others have discussed.
In general practice, I come across all of these. And on a bad day, (1) seems to predominate ;-) Cheers Paul Glasziou
Jon Brassey wrote:
> Hello All,
>
> I may be missing the point, but do others get frustrated with the term
> uncertainty in medicine? I've just received another pile of
> promotional material from a publisher who's highlighting uncertainty
> in medicine and insinuating their evidence is the answer. Surely,
> 'all' evidence does is quantify the uncertainty? For instance a drug
> may have a NNT of 25 - where's the certainty in that?
>
> Here's hoping for some serious and lighthearted responses.
>
> Best wishes
>
> jon
>
> Jon Brassey
> TRIP Database
> www.tripdatabase.com <http://www.tripdatabase.com/>
>
>
>
>
--
Paul Glasziou
Director, Centre for Evidence-Based Medicine, Department of Primary Health Care, University of Oxford www.cebm.net ph - +44-1865-289298 fax +44-1865-289287
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