Just to say that different conclusions to similar trial results for different interventions fits rather well with a Bayesian approach to statistics. In a Bayesian analysis prior beliefs are combined with new evidence to produce the 'current' (posterior) (rational) belief. If prior belief for the true effect of eg a homeopathic treatment is that (due to quite good understanding of physics of water, and mathematics of dilution) it is very likely to be close to zero - then it is going to take some very strong evidence to shift the posterior belief appreciably. As you say this is appropriate since it is effectively going to mean major revisions in the physics of materials / quantum mechanics ...
Cheers
David
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Tel: (01224) 554195
Senior Statistician
Immpact Project
University of Aberdeen
________________________________
From: Evidence based health (EBH) [mailto:[log in to unmask] <mailto:[log in to unmask]> ] On Behalf Of Adam LaCaze
Sent: 08 January 2009 22:19
To: [log in to unmask]
Subject: Re: Social Epistemology - I wonder if they believe in evolution - after all it explains biology and without that we don't even have .......
Hi Donald,
I have had a quick read of Derkatch's paper and my point is simply that there is no attack on science in what she is arguing (at least none that I can see).
I take her to be discussing the kind of argument that sometimes occurs between some proponents of CAM and the broader medical fraternity.
EBM provides a clear criteria for testing CAM treatments: test the treatment in a well conducted randomised trial. One problem is that too few CAM treatments have been subjected to well conducted randomised trials. A second problem (and the issue Derkatch discusses) arises when the CAM treatment has been subjected to a well conducted randomised trial. If the trial provides positive results, and the CAM treatment is sufficiently dubious (in the sense that a scientific theory for how the treatment might work is absent, eg homeopathy) then,---appropriately I think---many in the medical community will pay particular attention to the trial's methodology (something must be introducing a bias), or write off the results to chance.
Conversely, if the trial provides negative results then, sometimes at least, CAM proponents will do some special pleading. Something about the trial methodology, randomisation or control or something, has interfered with the CAM treatment's "true" causal process. I understand this is the case in trials of homeopathy. Despite good and growing evidence of ineffectiveness some CAM proponents push for more trials to be done.
EBM puts forward a clear test for efficacy which focuses on the methodology of research. Derkatch notes that despite the same methodology (RCTs), and despite many of the arguments being made in the name of methodology, CAM treatments are debated in different terms, and sometimes need to meet a different criteria in order to be considered efficacious. I stand to be corrected, but I don't think she is claiming too much more than that.
If I have understood correctly, I would suggest that something like this claim is true. And not only true but appropriate. RCTs of highly implausible treatments (CAM or not) are treated differently to RCTs of more plausible treatments. (For instance, I approach and make different arguments about the Kirsch PLOS Medicine 2008;5(2) meta-analysis of antidepressant trials than I do a meta-analysis of homeopathy trials, and at least part of this difference is explained by my attitude to the effectiveness of antidepressants compared to homeopathy). I would look to justify this difference in terms of the coherence of the theories or some other such approach (for what its worth I think attempts to justify the different approach raises a series of interesting questions).
Derkatch points to a difference in the arguments put forward about treatments that are tested in randomised trials. I think there is a good reason for that difference but that is different argument. Derkatch does not judge the arguments put forward by mainstream medics or CAM proponents, and perhaps some find her approach to the kind of arguments she is entertaining from CAM proponents too concessionary. Fair enough.
Best,
Adam
On 08/01/2009, at 10:27 PM, donald stanley wrote:
Dear Adam,
Your claim beginning: "Indeed the central thesis appears to be . . ." would you tell us how different, in what way, the assessment tools are, and which tools?
Donald
207-563-1560
________________________________
From: Adam LaCaze <[log in to unmask]>
Reply-To: Adam LaCaze <[log in to unmask]>
Date: Thu, 8 Jan 2009 20:32:01 +1000
To: <[log in to unmask]>
Subject: Fwd: Social Epistemology - I wonder if they believe in evolution - after all it explains biology and without that we dont even have .......
I realise the thread has developed a life of its own and many who have commented have not had a chance to read the papers, but it seems worth noting that the articles in the collection of Social Epistemology are firmly in the analytic tradition. (I assume the editors and other contributors would find the suggestion they may be deniers of evolution rather comic).
Perhaps Colleen Derkatch's article, which utilises literary or critical theory to discuss methodological debates in EBM and CAM, can be labelled "postmodern". However, even if the label is correct I don't see the perceived attack on medical knowledge or science that is being suggested. Indeed the central thesis appears to be not too different to one of the contributions to this thread: in strictly methodological terms we often assess well conducted randomised trials of complementary treatments in a different way to well conducted randomised trials of treatments considered within the standard purview of medicine---and that this in itself raises interesting questions.
The thesis is contestable, and some of the details of the paper can be argued (as some have discussed), and the method of analysis is that of rhetorical theory rather than standard analytic philosophy or discussions in the medical literature, but it is not "nuts", at least not the kind of nuts that is being implied.
Kind Regards
Adam
Begin forwarded message:
From: "Martin Dawes, Dr." <[log in to unmask]>
Date: 7 January 2009 1:28:01 AM
To: [log in to unmask]
Subject: Social Epistemology - I wonder if they believe in evolution - after all it explains biology and without that we dont even have .......
Reply-To: "Martin Dawes, Dr." <[log in to unmask]>
If we want some perspective on science and controversy can I bring to the table the anniversary of Darwin born 200 years ago, whose seminal book was published 150 years ago almost to the day. Intelligent design is rife in the United States where 47% of the population do not believe the evolutionary theory despite the evidence of many years work. What makes this particularly relevant to us is that without the theory of evolution we would not either have biology as we now know it or, for example, understand the mechanisms of drug metabolism.
While I am not suggesting complacency about this sort of ill informed criticism of EBM I do think it helps to know that we are not alone as scientists and that we are in for a very very very long debate.
Martin
-----Original Message-----
From: Evidence based health (EBH) [mailto:[log in to unmask] <mailto:[log in to unmask]> ] On Behalf Of Frances Gardner
Sent: 06 January 2009 08:52
To: [log in to unmask]
Subject: Re: Special Issue: Evidence in Evidence-Based Medicine Fw: Social Epistemology
Donald
"A House Built on Sand" ed. Noretta Koertge-
good thinking- this is a very interesting book; for me it was an eye-opener
to find that people also criticise physics in some similar ways to EBP.
you can find some similar material on the web eg papers by Sokal:
http://www.ee.bgu.ac.il/~censor/katz-directory/01-07-17sokal-lingua-franca-experiment.pdf <http://www.ee.bgu.ac.il/~censor/katz-directory/01-07-17sokal-lingua-franca-experiment.pdf>
or read an excerpt here, or buy it cheap on Amazon
http://www.amazon.co.uk/gp/reader/0195117255/ref=sib_rdr_ex?ie=UTF8&p=S00N&j=0#reader-page <http://www.amazon.co.uk/gp/reader/0195117255/ref=sib_rdr_ex?ie=UTF8&p=S00N&j=0>
Frances Gardner
Professor of Child and Family Psychology
Fellow of Wolfson College
Department of Social Policy and Social Work
University of Oxford, 32 Wellington Square, Oxford OX1 2ER, UK
tel 44 [0] 1865 270334 / 270325 fax 270324
e-mail: [log in to unmask]
----- Original Message -----
From: "donald stanley" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 06, 2009 1:27 PM
Subject: Re: Special Issue: Evidence in Evidence-Based Medicine Fw: Social
Epistemology - informaworld
Most of you probably know that the debate goes on and on. It generates
more
titles similar to those heard at the MLA meetings beginning about 25 years
ago.
May I recommend a summary of & commentary on the current topic in:
"A House Built on Sand"
ed. Noretta Koertge
ISBN 0-19-511725-5
Sifting through the stream of ironies, tropes and neologisms Philip
Kitcher
tries to make some sense of what is salvageable.
Donald Stanley
The University of Aberdeen is a charity registered in Scotland, No SC013683.
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