Brian D.M. Tom


MRC Biostatistics Unit
Institute of Public Health
University Forvie Site
Robinson Way
Cambridge CB2 0SR
United Kingdom

(Internal: Addenbrooke's Box No. 113)

Tel: +44 1223 330382
Fax: +44 1223 760727
E-mail: brian.tom at

Since December 2001, I have been a research statistician at the Medical Research Council Biostatistics Unit in Cambridge. Prior to this I worked as a consulting statistician and project statistician within the (now defunct)  University of Cambridge Department of Public Health and Primary Care's Centre for Applied Medical Statistics (CAMS) (1997-2000) and Epidemiology for Policy Group (2000-2001) respectively. I currently lead the Stratified Medicine Initiative at the Unit. Prior to this I worked within Professor Vern Farewell's programme for "Statistical Modelling: theory and applications" which deals with methods of statistical inference for challenging data structures. However, I also collaborate with other senior scientists (present and former) in the Unit, in particular Professor Sheila Bird, Dr Daniela De Angelis, Professor Wally Gilks and Professor Carlo Berzuini.

Current research interest:

  • Causal Inference
  • Chronic Disease Epidemiology (in particular related to Inflammatory Arthritis)
  • Dynamic Graphical Modelling of Stochastic Processes
  • Efficiency
  • Modelling of Longitudinal and Correlated Data
  • Multi-state Models and Survival Data
  • Stratified Medicine

Selected publications:

  • Tom B D M, Farewell V T, Bird SM. Maximum likelihood and pseudo score approaches for parametric time-to-event analysis with informative entry times. Annals of Applied Statistics 2014; 8(2): 726-746. [Article]
  • Farewell V T, Tom B D M. The versatility of multi-state models for the analysis of longitudinal data with unobservable features. Lifetime data analysis 2014; 20: 51-75. [Article]
  • Tom B D M, Su L, Farewell V T. A corrected formulation for marginal inference derived from two-part mixed models for longitudinal semi-continuous data. Statistical Methods in Medical Research.
    (OnlineFirst 6 November 2013)
  • Su L, Tom B D M, Farewell V T. A likelihood-based two-part marginal model for longitudinal semicontinuous data. Statistical Methods in Medical Research.
    (OnlineFirst 25 August 2011)
  • Tom B D M, Farewell V T. Intermittent observation of time-dependent explanatory variables: A multi-state modelling approach. Statistics in Medicine 2011; 30(30): 3520-3531.
  • O'Keeffe A G, Tom B D M, Farewell V T. A case study in the clinical epidemiology of psoriatic arthritis: Multi-state models and causal arguments.
    Journal of the Royal Statistical Society, Series C 2011; 60(5): 675-699.
  • Ajduk A, Ilozue T, Windsor S, Yu Y, Seres K B, Bomphrey R J, Tom B D, Swann K, Thomas A, Graham C, Zernicka-Goetz M. Rhythmic actomyosin-driven contractions induced by sperm entry predict mammalian embryo vitality. Nature Communications 2011; 2:417.
  • Presanis A M, Pebody R G, Paterson B, Tom B D M, Birrell P J, Charlett A, Lipsitch M, De Angelis D. Changes in severity of pandemic (H1N1) 2009 influenza in England:
    a Bayesian evidence synthesis. BMJ 2011; 343:d5408.
  • Tom B D M, Van Hoek A J, Pebody R, McMenamin J, Robertson C, Catchpole M, De Angelis D. Estimating time to onset of swine influenza symptoms after initial novel
    A(H1N1v) viral infection. Epidemiology and Infection 2011; 139(9): 1418-1424. (FirstView Articles 19 November 2010)
  • Husted J A, Tom B D, Farewell V T, Gladman D D. Longitudinal analysis of fatigue in psoriatic arthritis (PsA). Journal of Rheumatology 2010; 37(9): 1878-1884. (Online First 1 July 2010) [Abstract]
  • Farewell V T, Tom B D M. Commentary on "Measurement in clinical trials: a neglected issue for statisticians?" by S Senn and S Julious. Statistics in Medicine
    2009; 28(26): 3210-3212.
  • Tom B D M, Farewell V T. Statistical methods for individual-level data in cohort mortality studies of rheumatic diseases. Communications in Statistics - Theory and Methods 2009; 38(18): 3472-3487.
    (Addendum: Figures 1 and 2 have been switched around mistakenly.)
  • Fu B, Tom B D M, Bird S M. Re-weighted inference about hepatitis C virus-infected communities when analysing diagnosed patients referred to liver clinics. Statistical Methods in Medical Research 2009; 18(3): 303-320. (OnlineFirst 26 November 2008) [Abstract]
  • Su L, Tom B D M, Farewell V T. Comments on "A hierarchical zero-inflated log-normal model for skewed responses". Statistical Methods in Medical Research 2009; 18(1): 107-108. [Letter to Editor]
  • Su L, Tom B D M, Farewell V T. Bias in 2-part mixed models for longitudinal semicontinuous data. Biostatistics 2009; 10(2): 374-389. (Advance Access 8 January 2009) [Article]
  • Husted J A, Tom B D, Schentag C T, Farewell V T, Gladman D D. Occurrence and Correlates of Fatigue in Psoriatic Arthritis (PsA). Annals of Rheumatic Diseases 2009; 68: 1553-1558. (Online First 17 October 2008) [Abstract]
  • Gladman D D, Schentag C T, Tom B D M, Chandran V, Bhimani M, Teshima C, Brockbank J, Farewell V T. Development and Initial Validation of a Screening Questionnaire for Psoriatic Arthritis: The Toronto Psoriatic Arthritis Screen (ToPAS). Annals of Rheumatic Diseases 2009; 68: 497-501. (Online First 30 April 2008) [Abstract]
  • Urowitz M B, Gladman D D, Tom B D M, Ibañez D, Farewell V T. Changing Patterns in Mortality and Disease Outcomes for Systemic Lupus Erythematosus (SLE) Patients. Journal of Rheumatology 2008; 35(11): 2152-8. (First Release online 15 September 2008) [Abstract]
  • Burns P, Gusnanto A, Macaulay I C, Rankin A, Tom B, Langford C F, Dudbridge F, Ouwehand W H, Watkins N: on behalf of the BLOODOMICS Consortium. Identification of variation in the platelet transcriptome associated with Glycoprotein 6 haplotype. Platelets 2008; 19(4): 258-267. [Abstract]
  • Rohekar S, Tom B D M, Hassa A, Schentag C T, Farewell V T, Gladman D D.
    Prevalence of malignancy in psoriatic arthritis. Arthritis and Rheumatism 2008; 58(1): 82-87. [Abstract] and [Article]
  • Fu B, Tom B D M, Delahooke T, Alexander G J M, Bird S M. Event-biased referral can distort estimation of hepatitis C virus progression rate to cirrhosis, and of prognostic influences. Journal of Clinical Epidemiology 2007; 60(11): 1140-1148. [Abstract]
  • Farewell V T, Tom B D M. Discussion of Zeng D and Lin D Y "Maximum likelihood estimation in semiparametric regression models with censored data." Journal of the Royal Statistical Society, Series B 2007; 69(4): 507-564 (see pp 543-544).
  • Ali Y, Tom B D M, Schentag C T, Farewell V T, Gladman D D. Improved survival in psoriatic arthritis with calendar time. Arthritis and Rheumatism 2007; 56(8): 2708-2714. [Abstract] and [Article]
  • Jones C I, Garner S F, Angenent W, Bernard A, Berzuini C, Burns P, Farndale R W, Hogwood J, Rankin A, Stephens J C, Tom B D, Walton J, Dudbridge F, Ouwehand W H,Goodall AH (on behalf of BLOODOMICS consortium). Mapping the platelet profile for functional genomic studies and demonstration of the effect size of GP6 locus. Journal of Thrombosis and Haemostasis 2007; 5(8): 1756-1765. [Abstract] and [Article]
  • Gusnanto A, Tom B, Burns P, Macaulay I, Thijssen-Timmer D C, Tijssen M R, Langford C, Watkins N, Ouwehand W, Berzuini C, Dudbridge F. Improving the power to detect differentially expressed genes in comparative microarray experiments by including information from self-self hybridizations. Computational Biology and Chemistry 2007, 31: 178-185. [Abstract]
  • Husted J A, Tom B D, Farewell V T, Schentag C T, Gladman D D. A longitudinal study of the effect of disease activity and clinical damage on physical function over the course of psoriatic arthritis (PsA): Does the effect change over time? Arthritis and Rheumatism 2007; 56(3): 840-849. [Abstract] and [Article]
  • Gilks W R, Tom B D M, Brazma A. Fusing microarray experiments with multivariate regression. Bioinformatics 2005; 21 Suppl 2: ii137-ii143. [Article] [Peppered Fried Egg Plot]
  • Tom B D M, Gilks W R, Brooke-Powell E, Ajioka J. Quality Determination and the Repair of Poor Quality Spots in Array Experiments. BMC Bioinformatics 2005; 6(1):234. [Article]
  • Husted J A, Tom B D, Farewell V T, Schentag C, Gladman D D. Description and Prediction of Physical Functional Disability in Psoriatic Arthritis (PsA): A Longitudinal Analysis Using a Markov Model Approach. Arthritis Care & Research 2005; 53(3): 404-409. [Abstract] and [Article]
  • Farewell V T, Tom B D M, Royston P. The impact of dichotomization on the efficiency of testing for an interaction effect in exponential family models. Journal of the American Statistical Association 2004; 99(467): 822-831. [Abstract]
  • Melzer D, Lan T-Y, Tom B D M, Deeg D J H, Guralnik J M. Variation in thresholds for reporting mobility disability between national population sub-groups and studies. Journal of Gerontology: Medical Sciences 2004; 59:1295-1303. [Abstract]
  • Tyrer P, Tom B, Byford S, Schmidt U, Jones V, Davidson K, Knapp M, MacLeod A, Catalan J; POPMACT Group. Differential effects of manual assisted cognitive behavior therapy in the treatment of recurrent deliberate self-harm and personality disturbance: the POPMACT study. Journal of Personality Disorders 2004; 18(1): 102-116. [Abstract] and [Article]
  • U-King-Im J M, Trivedi R A, Graves M J, Higgins N J, Cross J J, Tom B D, Hollingworth W, Eales H, Warburton E A, Kirkpatrick P J, Antoun N M, Gillard J H. Contrast-enhanced MR angiography for carotid disease: Diagnostic and potential clinical impact. Neurology 2004; 62: 1282-1290. [Abstract]
  • Melzer D, Tom B D M, Brugha T, Fryers T, Gatward R, Grounds A, Johnson T, Meltzer H. Access to Medium Secure Psychiatric Care in England and Wales 1: A National Survey of Admission Assessments. Journal of Forensic Psychiatry and Psychology 2004; 15 (1): 7-31. [Abstract]
  • Borthwick J M, Charnock-Jones D S, Tom B D M, Hull M L, Teirney R, Phillips S C, Smith S K. Determination of the transcript profile of human endometrium. Molecular Human Reproduction 2003; 9(1): 19-33. [Article] [Figures featured on Journal's Cover]
  • Lan T-Y, Melzer D, Tom B D M, Guralnik J M. Performance Tests and Disability: Developing an objective index of mobility-related limitation in older populations. Journal of Gerontology: Medical Sciences 2002; 57(5): M294-301. [Abstract]
  • Melzer D, Tom B D M, Brugha T, Fryers T, Grounds A, Johnson A L, Meltzer H, Singleton N. Prisoners with Psychosis in England and Wales: a one year national follow-up study. The Howard Journal of Criminal Justice 2002; 41(1): 1-13. [Abstract]
  • Martoglio A-M, Tom B D M, Starkey M, Corps A, Charnock-Jones S D, Smith S K. Changes in Tumorigenesis- and Angiogenesis-Related Gene Expression in Ovarian Cancer Detected by Tailored High Density cDNA Arrays. Molecular Medicine 2000; 6(9): 750-765. [Article]
  • Caronia S, Taylor K, Pagliaro L, Carr C, Palazzo U, Petrik J, O'Rahilly S, Shore S, Tom B D M, Alexander G J M.
    Further evidence for an association between non-insulin dependent diabetes mellitus and chronic hepatitis C virus infection. Hepatology 1999; 30(4): 1059-1063. [Abstract] and [Article]


I was an affiliated lecturer in the University of Cambridge Statistical Laboratory where I jointly taught (with Dr. Susan Pitts and Dr. Davide Pigoli) the Applied Statistics course on the
Master of Mathematics/Master of Advanced Study (Part III of the Mathematical Tripos). I have also previously lectured on and been an examiner for the
M.Phil in Epidemiology here at the Institute of Public Health, and in the past
given a one-day course on "Handling Of Time-To-Event Data" for CAMS. I have also lectured and demonstrated on the European Union Sixth Framework Programme funded project Molecular Phenotype to Accelerate Genomic Epidemiology (MolPAGE) Training Course hosted in Pavia, Italy.

Below are my Applied Statistics Lecture Notes, Slides and R Practicals for Lent 2015

I have also contributed encyclopaedic entries to the Encyclopaedic Companion to Medical Statistics.


Below is a talk I gave at the 2nd Clinical Trials Workshop at the MRC Biostatistics Unit on Subgroup Analysis

Below is my internal MRC Biostatistics Unit presentation on interfacing R with C

Below is a talk I gave to the Cambridge Statistical Discussion Group (CSDG) on Psoriatic Arthritis

Below is my invited presentation at the 28th Annual Conference of the International Society for Clinical Biostatistics (ISCB28) in Alexandroupolis

Below is my presentation at the Armitage Workshop on Epidemiological Methods held at the Max Perutz Lecture Theatre, MRC LMB in Cambridge

Below is my internal MRC Biostatistics Unit presentation on Time-Varying Confounding


Here is a list of links to people and projects that I have been associated with over the last few years


Last updated: 4 May 2016