Table Of ContentThe statistical consultant in action
EDITORS: D. J. HAND AND B. S. EVERITT
The statistical consultant
in action
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© Cambridge University Press 1987
First published 1987
Printed in Great Britain by the University Press, Cambridge
British Library cataloguing in publication data
The Statistical consultant in action.
1. Mathematical statistics
I. Hand, D. J. II. Everitt, Brian
519.5 QA276
Library of Congress cataloguing in publication data
The Statistical consultant in action.
Bibliography
1. Statistical consultants. 2. Statistics.
I. Hand, D. J. II. Everitt, Brian.
QA276.17.S73 1987 001.4'22 86-17159
ISBN 0 521 30717 1
Contents
Preface vii
List of contributors xi
1 Statistical consultancy 1
D. J. Hand and B. S. Everitt
2 Consultants' cameos: a chapter of encounters 11
Tony Greenfield
3 Straight consulting 26
V. Barnett
4 A two-period crossover trial 42
D. Clayton and M. Hills
5 Consultancy in a medical school, illustrated by a clinical
trial for treatment of primary biliary cirrhosis 58
D. G. Cook and S. J. Pocock
6 The analysis of response latencies 72
G. Dunn
7 Acid rain and tree roots: an analysis of an experiment 80
/. N. R. Jeffers
8 On identifying yeasts and related problems 108
J. C. Gower and R. W. Payne
9 Uneven sex ratios in the light-brown apple moth:
a problem in outlier allocation 121
Toby Lewis
10 Collaboration between university and industry 134
B. J. T. Morgan, P. M. North and S. E. Pack
11 Inspection for faulty components before or after assembly
of manufactured items 153
P. M. E. Altham
vi Contents
12 Statistical modelling of the EEC Labour Force Survey:
a project history 171
M. Aitkin and R. Healey
Bibliography on statistical consulting 180
D. J. Hand
Name index 183
Subject index 186
Preface
In an article published in 1970 Professor A. Ehrenberg made the following
comment:
41 feel that the kind of examples of statistical analysis that tend
to be considered in professional discussions... are so grossly
over-simplified as to make a pretentious mockery of real-life
situations and statistical consultancy.'
Examining some of the examples presented in many statistical text-
books, we were forced to agree with Professor Ehrenberg - a comparison
of the average weekly beer consumption of male college students living
in halls-of-residence with those not living on campus hardly gives the
flavour of most real-world consultancy problems!
So in an attempt to present the reality of statistical consulting we were
led to assemble the collection of papers that make up this text. Our aim
was to show that, in addition to statistical expertise of the type acquired
from standard textbooks and in courses held up and down the country,
the consultant statistician needs a number of other talents, foremost of
which is the ability and willingness to communicate with researchers in
other areas. We see this book as a complement to standard texts and ideally
we would like to see it adopted as a companion volume on statistics
courses, covering those parts of statistical consultancy which are not (and
perhaps cannot be) formally taught.
Since statistical problems arise in almost all areas of science, in medicine,
in industry, in marketing and in finance, so do problems related to
statistical consultancy. Adequate coverage of all these areas could only be
achieved in a text containing many hundreds of articles. Nevertheless in
the twelve contributions enclosed here we hope a relatively wide spectrum
of interests is catered for, and we believe that the problems identified and
viii Preface
the general comments made will be applicable in areas not specifically dealt
with.
We have attempted to order chapters so that those dealing with similar
areas occur close to one another, although this is not always possible simply
because several chapters deal with more than one area of application.
The opening chapter presents an overview of the world of the statistical
consultant, exploring how different areas of work and different working
environments influence the opportunities and problems.
In Chapter 2 Tony Greenfield reminds us that one major difference
between British and Japanese industry is that in Japan many millions of
people are trained in the use of statistical methods. He presents a case for
greater employment of statistical consultants in manufacturing industry
and provides an entertaining series of anecdotes about the difficulties
which a consultant statistician can encounter.
Professor Barnett, in Chapter 3, presents three case studies, each of
which began with a request to 'just help me to fit a straight line to these
data'. One is in archaeology and two are in medicine. He uses these
examples to show how real problems motivate methodological research,
and notes that few subjects can advance nowadays without the proper use
of statistical methods.
Crossover designs play a very important role in medical applications of
statistics, especially in clinical trials. Clayton and Hills (Chapter 4) present
an introduction to the merits and problems of such designs, and then show
how theoretical ideals are adapted to practical necessities by examining
the analysis of a real crossover design. They also give advice on prepara-
tion of the report, noting that different recipients - here a pharmaceutical
company and clinical investigator - will expect different things in the
report.
In Chapter 5 Cook and Pocock describe some of the ethical issues which
arose during a clinical trial, and illustrate the necessity of being able to
explain the analyses to the client.
Graham Dunn, in Chapter 6, shows how consultation can be aimed at
educating the client, so enabling them to conduct future analyses on their
own. He points out the importance of providing an analysis that the client
can understand.
Not all consultations are ideal from the statistician's viewpoint. Jeffers
(Chapter 7) presents a case in which the consultant statistician had to do
his best with data arising from an experiment which was designed and
conducted without seeking statistical advice. The case in point is a study
of the topical subject of acid rain, and demonstrates how vital it is for the
statistician to have some specialist knowledge of the subject matter.
Preface ix
In Chapter 8 Gower and Payne demonstrate how problems presented
to the statistical consultant can stimulate the development of both
methodology and computer programs.
Lewis (Chapter 9) describes how an unusual outlier problem arose
during an investigation of uneven sex ratios in moths. A follow-up on the
moths' descendants shows that one cannot afford to be too dogmatic in
presenting the results to the clients.
In Chapter 10 Morgan, North and Pack describe collaboration between
university and industry, pointing out the special requirements of industrial
statistical consultancy, and showing how effective such collaboration can
be. They illustrate the benefits which can following from having a con-
sultancy unit attached to a university department of statistics.
Altham, in Chapter 11, describes a problem from manufacturing in-
dustry, and demonstrates how simulation can be effective in communi-
cating with the client.
Earlier chapters have described relatively small case studies. Aitkin and
Healey (Chapter 12) complement these by describing the management of
a study of modelling a large body of socio-economic data.
Finally, for those who wish to pursue further any of the non-statistical
aspects of consulting, we present a bibliography on statistical consultancy.
We hope that the material in this book will show the budding statistician
that statistical consultancy work provides a very broad spectrum of
interesting and intellectually stimulating problems. The working environ-
ments are equally varied, ranging from university mathematics depart-
ments, via specialist advisory units, to freelance industrial and commercial
work. Few other professions provide one with the opportunity to contribute
significantly to progress in such a wide diversity of disciplines.
Lastly it is a pleasure to express our sincere thanks to all our contributors
for the speed with which they responded to our invitation to submit articles
and for their forebearance when, where necessary, they were reminded of
'deadlines' (realistic or not!).
D. J. Hand
B. S. Everitt
