THE CAMBRIDGE STATISTICS DISCUSSION GROUP
Monday 13th March 2006 7:15 for 7:45
Small Lecture Theatre,
Department of Plant Sciences,
Downing Site,
Cambridge
Analysing Imperfect Randomised Trials
Ian White
M.R.C Biostatistics Unit
Abstract:
In a perfect randomised trial, everyone receives their randomised treatment.
Most randomised trials in medicine fail to achieve this ideal.
Conventionally they are analysed by intention-to-treat which estimates
relative merits of different treatment policies, but other methods are
required if the relative merits of the actual treatments are of interest. A
common alternative is per-protocol analysis, but this is subject to
selection bias. I will introduce randomisation-based methods of causal
inference, which avoid both problems. They are not widely used, perhaps
because of their complexity and unfamiliarity to many statisticians. I will
give some examples where randomisation-based causal inference has given
useful conclusions.
Speakers:
Ian White is Senior Scientist at the Medical Research Council's
Biostatistics Unit in Cambridge, and was previously Senior Lecturer in the
Medical Statistics Unit at the London Schoool of Hygiene and Tropical
Medicine. After studying mathematics at Cambridge University, his first
career was as a teacher of mathematics in The Gambia, Cambridge and London.
He then obtained his MSc in statistics from University College London, where
he subsequently worked in the Department of Epidemiology and Public Health.
His main research interest is the analysis of clinical trials, in particular
dealing with departures from randomised treatment, missing data, and
subgroup analysis. He collaborates on various clinical trials and
observational studies. He is also interested in statistical methods in
epidemiology, in particular dealing with measurement error, and in
meta-analysis.
Directions:
The Department of Plant Sciences is located on the Downing site situated
between Downing Street and Tennis Court Road. Go through the second door you
come to in the building immediately on your left as you enter from Tennis
Court Road. Once inside the building follow the arrows.
It is not possible to park on the Downing site in the evening. The nearest
car park is at Lion Yard. Arrivals after 7:45pm can gain admittance by
contacting the secretary on 07761769436.
Next Meetings:
3rd April - Rebecca Turner (Biostatistics) on 'Design of cluster randomised
trials, using empirical evidence on the intracluster correlation coefficient'.
4th May - Adam Kleczkowski (Plant Sciences) on 'Parameter estimation and
prediction for the course of a single epidemic'. CONFIRM TITLE
Supper: Some members eat regularly in the University Centre before
each talk meeting in the downstairs bar at 5-45pm. Feel free to join them.
Subscriptions: of 4 pounds per attender are now due for the 2005-2006 session.
Secretary: Peter Watson, MRC Cognition and Brain Sciences Unit,
15 Chaucer Road, Cambridge CB2 2EF;telephone 01223 355294 Extension 801;
E-mail [log in to unmask]
|