THE CAMBRIDGE STATISTICS DISCUSSION GROUP Thursday 30th November 2000 7:15 for 7:45 Statistical Laboratory, Centre for Mathematical Sciences, Wilberforce Road Cambridge Approaches to the analysis of longitudinal studies with dropout: cognitive function and aging David Clayton, M.R.C. Biostatistics Unit, Cambridge Abstract: Typically the analysis of longitudinal studies of cognitive decline in the elderly is complicated by the fact that cohorts suffer considerable attrition during the follow-up period. It is important to make a clear distinction between attrition due to death and that due to drop-out, since these should not necessarily be treated in the same way in the analysis. In neither case will it generally be realistic to assume data to be missing at random. This presentation will compare a subject-specific modelling strategy for such data (implemented in BUGS) with a marginal modelling strategy implemented by weighted estimating equations (in STATA). Speaker: David started out as a psychologist, but gravitated to Medical Statistics and Epidemiology in the late 1960's, working at the London School of Hygiene and Tropical Medicine, first as a computer programmer in the department of Epidemiology and Medical Statistics and then as a statistician in the MRC Social Medicine Unit. He then spent 14 years as a Senior Lecturer in Biostatistics in the Medical School of the University of Leicester until joining the MRC Biostatistics Unit in 1990. His interests have largely been in the application of Statistics to Epidemiology but have focussed in recent years on Genetic Epidemiology. As a result of this evolution of his interests he will shortly leave the BSU to take up a Wellcome Trust Principle Research Fellowship in the Wellcome Trust Centre for the Study of Molecular Mechanisms of Disease within the Department of Medical Genetics. Directions: The main entrance is reached from Clarkson Road by going left of the Newton Institute, and following the path round by the edge of a building site to the building (Pavilion A) with a glass front and a curved grassed roof. The main entrance is in the middle of the glass front. Coffee before the talk will be in the common room in Pavilion D, and the talk will be in Meeting Room 4 in Pavilion A. Free Parking is available after 5pm on Clarkson and Wilberforce Roads. Next Meetings: 8th February - Graham Healey (Huntingdon Life Sciences) on 'Some recent progress in the design of regulatory toxicity studies'. 8th March - John Barrett (Genetics). 10th May - Jennifer Potts (Cognition and Brain Sciences Unit). Provisional: 5th April - Judith Quinlan (SmithKline Beecham). Supper: Some members eat regularly in the University Centre before each meeting at 6-15. Feel free to join them. Subscriptions: of 4 pounds per member are now due for the 2000-2001 session. Cheques should be made payable to Robert Milroy and may be posted to the secretary at the address below. Secretary: Peter Watson, MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 2EF;telephone 01223 355294 Extension 380; E-mail [log in to unmask] %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%