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]





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