Dictionary of Evidence-based Medicine.pdf

46 Dictionary of Evidence-based Medicine
theories), decision scientists also study how decision makers (individuals,
groups or organizations) identify problems which need addressing and
how they learn from the results of their actions (descriptive theories). The
field of decision sciences has its roots in many disciplines, including
economics, management science, philosophy, psychology, social science
and statistics. Medical decision making, which draws heavily on the
clinical sciences as well as the above disciplines, has been the subject of
much development over the past three decades (Kleindorfer PR,
Kunreuther HC, Schoemaker PJH (1993) Decision sciences. Cambridge
University Press, Cambridge).
Defined daily dose
The defined daily dose (DDD) is a measure of the standard daily therapeutic
dose. The number of defined daily doses is obtained by dividing the
total amount of drug prescribed by the defined daily dose for the drug. For
example, the defined daily dose of ranitidine is 300 mg. Therefore, if a
practice prescribes 150 000 mg of the drug, this is equivalent to 500 DDDs.
The World Health Organization publishes a list of DDDs for various drugs
(WHO (1997) Guidelines for defined daily doses. WHO, Geneva).
Delphi technique
The Delphi technique is a consensus method for making forecasts. In health
care it is often used for making predictions about costs or demands for
health care services whenever reliable data for making objective predictions
are not available. The Delphi technique has, for example, been used
for predicting the epidemiology of acquired immune deficiency disease so
that health care provisions for such patients can be planned and for predicting
the course of progression of hairy cell leukaemia in patients treated
with or without interferon (Ozer H, Golomb HM, Zimmerman H, Spiegel
RJ (1989) Cost-benefit analysis of interferon Alfa-2b in the treatment of
hairy cell leukaemia. Journal of the National Cancer Institute. 81: 594-602).
The Delphi technique is usually classified as a qualitative research method
although the predictions being made are usually quantitative. Usually
three different types of participants are involved in the Delphi process:
(i) decision makers, who are a group of experts who will make the forecast;
(ii) staff personnel who will assist in the administration of the project;
(iii) expert respondents whose judgements are valued.
Once the three groups have been selected, the following steps take place:
(i) development and administration of the first questionnaire; (ii) analysis
of the results of the first questionnaire; (iii) development and administration