John Nelder: from general balance to generalised models (both linear and hierarchical)

A personal portrait of some aspects of John Nelder's life, personality and work is given. Introduction: some personal remarks Some personal remarks are in order, since the reader will be baffled as to how a medical statistician such as myself, a practitioner rather than a theoretician, can be a suitable person to give an overview of John Nelder's work in statistics, which has been powerful and deep, and whose importance is only 'applied', rather than 'theoretical', in the sense that it is of great utility to many practitioners in many fields. In fact, this introduction will provide more of a plausible excuse than a valid reason but at least the reader will have some understanding as to why I am writing this. I first met John Nelder when we were both lecturers at the annual one-day meeting of the Swiss Statistical Association in the early 1990s. John's lecture made more of an impression on me than my own since I can remember that his was about, 'significant sameness' but cannot recall what I lectured on (either baseline balance or cross-over trials). There was little opportunity for us to talk to each other and I doubt that we exchanged more than a few words. We next met at the annual meeting of the PSI (Statisticians in the Pharmaceutical Industry) at Bournemouth in 1996. John lectured on Hierarchical Generalised Linear Models (of which more anon) and I on portfolio management but again we exchanged very few words, although I remember the meeting for another contribution of John's and that was that it was the first time I heard him play the piano. (This will also be covered anon.) However, shortly after the Bournemouth meeting I saw John standing on Harpenden station. I think all who know John will agree that he has an unmistakable appearance: that of a tall, commanding and striking figure who would satisfy any schoolboy's prejudice as to what a scientist should look like. (For some reason the old-fashioned English slang word 'boffin' springs to mind.) There was no mistaking the man and I plucked up courage and introduced myself properly to John this time and have counted myself as a friend, almost from that instant. John lives with his wife Mary in the village of Redbourn, which is only three miles from Harpenden, in which is situated Rothamsted research station, the statistical department of which has counted Fisher, Yates and also, of course, Nelder, amongst its heads. It is a curious fact that interests me that the rudest letter (with possible exception of one addressed to John Tukey) in the collected statistical correspondence of the first head of statistics at Harpenden is addressed to the man who was destined to become the third. From that you can judge that John Nelder is not deterred easily. Harpenden also has the nearest and most convenient station to Redbourn for getting in to London. Although John took early retirement from Rothamsted aged only 60, this made no difference to the interest he has had from an early age in statistics and he has been travelling in by train to Imperial College ever since. Since we are gathered here at Imperial to celebrate John's 80th Birthday, it is a simple calculation to determine that he has been doing this for 20 years. For seven of those years I was in the fortunate position of being a frequent travelling companion of John's, since from 1995-2003, while working at University College London, I lived in Harpenden and after our 1996 introduction frequently found myself on the same train as John. In fact, John's train-travelling habits have another relevance here since they exhibit many features that also find a parallel in his justifiably famed problemsolving and algorithmic abilities. First of all there is the choice of train. If you wish to get into London of a morning from Harpenden without paying peak time rates, you must wait until after 09:30. The first train