Please don't confuse decision aids with decision analysis. The former are
adjuncts, counseling aids "design to help people make specific and
deliberative choices" among different treatment options. The latter is "is
an explicit, quantitative method of clinical decision making that involves
SEPARATION of the probabilities of events from their relative values, often
called utilities".
It is customary to think about three theories of decision-making: 1)
normative theory describes how (rational) people SHOULD (or ought to) make
decisions, and is based on axiomatic mathematical or statistical concepts
(usually, the best course of action is the one that maximizes expected
utility), 2) descriptive theory recognizes that people often violate
normative principles of decision making and is concerned with understanding
HOW ("is vs. ought to") people actually make decisions, 3) prescriptive
theory deals with the question what should we do to IMPROVE our decision
making (such as developing decision aids).
Normative models are evaluated by their theoretical adequacy, that
is, the degree to which they provide acceptable idealizations or rational
choice.
Descriptive models are evaluated by their empirical validity, that
is, the extent to which they correspond to observed choices.
Prescriptive models are evaluated by their pragmatic values, that
is, by their ability to help people make better choices.
Now, it is not clear at all how to define "gold standard" of
decision-making. People have argued about that for decades, and I am not
sure that there is any good consensus about it.
Would be interesting to hear views of the members of this discussion
group.
ben
Benjamin Djulbegovic, MD
Associate Professor of Medicine
H. Lee Moffitt Cancer Center & Research Institute
at the University of South Florida
Division of Blood and Bone Marrow Transplant
12902 Magnolia Drive
Tampa, FL 33612
Editor: Evidence-based Oncology
e-mail:[log in to unmask]
http://www.hsc.usf.edu/~bdjulbeg/
phone:(813)979-7202
fax:(813)979-3071
> -----Original Message-----
> From: Guthrie, Dr Bruce [SMTP:[log in to unmask]]
> Sent: Wednesday, September 22, 1999 6:23 AM
> To: [log in to unmask]
> Cc: [log in to unmask]
> Subject: deciding if decision analysis is good
>
> Dear all,
>
> Since I'd been discussing decision analysis with a colleague, I was
> very interested to see a systematic review of decision aids in this
> weeks BMJ (BMJ 1999;319:731-734).
>
> The article shows that decision aids increase knowledge (a big effect
> but complex interventions didn't appear much better than simple ones)
> and reduced decisional conflict (I've no proper idea what a reduction
> in decisional conflict score of 0.3 out of 5 means, but from the way
> they describe it I'm not sure the effect is very big - any
> comments?). Only one of the studies cited appeared to use decision
> analysis and this involved doctors deciding on hep B vaccination.
>
> My reading of it is that simple measures to structure how you give
> patients information are helpful in at least some respects. There
> doesn't appear to be much evidence one way or the other on more
> complex aids like decision analysis.
>
> In EBM decision analysis is often written about as if it is the 'gold
> standard' of decision making (eg being the "black belt"
> interpretation of diagnostic tests in Clinical Epidemiology).
> We were wondering why it has achieved this status? I can see that it
> is intellectually attractive (logical, clear, explicit) but is there
> an evidence basis for it being what we should aspire to (since
> I currently feel a bit guilty about never attempting it)?
>
> Bruce
>
>
> 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]
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