Guidelines for the visual presentation of statistical data in the life sciences

Transcription

1 Charts & Graphs

2 Carts & Grap s Guidelines for the visual presentation of statistical data in the life sciences Editor Contri butors Illustrations Doig Simmonds Gillian Bragg Gillian Lee Martyn King David Tredinnick Gillian Bragg Published in association with The Institute of Medical and Biological Illustration MTa LIMITED International Medical Publishers LA"CAST ER BALrIMORE \IELBOUR"E

3 Published by MTP Press Limited Falcon House Lancaster, England in association with the Institute of Medical and Biological Illustration 27 Craven Street London WC2N 5NX Copyright ( Institute of Medical and Biological Illustration First published 1980 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission from the publishers. Cover design: Gillian Bragg British Library Cataloguing in Publication Data Charts and graphs. 1. Biometry 2. Statistics-Charts, tables, etc. 3. Medical statistics I. Simmonds, Ooig II. Bragg, Gillian III. Institute of Medical and Biological Illustration 574'.01 '82 QH323.5 ISBN ISBN (ebook) / iv

4 The Authors Doig Simmonds. Aol. AMA. is chief medical artist at the Royal Postgraduate Medical School. London. where he runs a highly successful 'Do-It-Yourself' art studio. Approximately 120 members of staff use these facilities and produce between drawings of publishable quality each month. He has been developing equipment and systems for standardization of statistical drawings since Gillian Bragg. BA. MMAA. AIMB!. studied at Brighton College of Art and Kingston College of Art, and was awarded the Diploma in Art and Design. Fine Art Sculpture in 1967, with the BA(Hons) degree conferred in She was a Medical Artist at Guy's Hospital Medical School for seven years, and during that time was awarded membership of the Medical Artists' Association and associateship of IMBI. Mrs Bragg was for four years in charge of the Art Section of the Department of Medical Illustration, Clinical Research Centre. Harrow. and is now a freelance illustrator. v

5 CHARTS & GRAPHS Gillian Lee, AIMBI, MMAA, was trained by the Medical Artists' Association at Guy's Hospital, and worked as Medical Artist at Guy's, The Institute of Urology, and St Bartholomew's Hospital. She is a founder associate of the Institute of Medical and Biological Illustration, and has been a freelance medical illustrator for eleven years. Martyn King, BA (Hons), studied typographic design at Leeds Polytechnic, and worked for two years as a typographer in the Medical Illustration Department, Clinical Research Centre, Northwick Park Hospital. He is at present a Senior Graphic Designer with the Graphics Unit, Reckitt and Colman Ltd, Hull. David Tredinnick, FRPS, AIMBI, is Head of the Department of Medical Illustration at St Bartholomew's Hospital and Medical School. He trained as a Medical Photographer at Westminster Hospital Medical School, and is a Fellow of the Royal Photographic Society and an Associate and Secretary of the Institute of Medical and Biological Illustration. vi

6 Contents IX ACKNOWLEDGEMENTS xi INTRODUCTION PUBLICATION 8 COPYRIGHT 12 SLIDES 18 ARTWORK FOR TELEVISION 21 TAPE/SLIDE PROGRAMMES Introduction-print area-lettering-size of original and its reduction-line thickness-tone-key symbols-original or copies-photographstables-'camera-ready copy' -suitable materialsco-operation with the publisher Copies-lectures-plagiarizing the work of otherspublication rights-freelance illustratorsinfringements of copyright-agreements-feesphotographers Introduction-functions, types and limitationsfactors affecting design-photography-comparable results Introduction-TV format and frame filling-blackand-white tones-colour-minimum line thicknesslettering Introduction-script-format-slide change-screen size-colour-type style-photography vii

7 CHARTS & GRAPHS 22 TYPE AND ITS USE 28 CHARTS AND GRAPHS 42 HISTOGRAMS, COLUMN AND BAR CHARTS Introduction-type-type usage-tables I ntroduction -general factors-graphs-scattergraphs-circular graphs Histograms-bar charts-column charts-area charts-notes concerning the illustration of percentages-labelling of axes in per centnomograms-pyramid graphs-pictograms-flow charts-genealogy charts-organization chartsusing the third dimension GLOSSARY APPENDICES 1. Some SI units and abbreviations in common use 2. Greek alphabet 3. Flow chart symbols 4. The use of some important chemical symbols 5. Amino acid residues 6. International paper sizes 7. Materials and equipment 8. Recommended suppliers (UK) 9. Major manufacturers of dry transfer (rub down) lettering and symbols 10. Sources and reference works viii

8 Acknowledgements This book is a result of a great deal of co-operation between individuals and organizations. In 1974 the Institute of Medical and Biological Illustration published a request by me for help and assistance with the gathering together of ideas concerning elementary standards for drawing statistical illustrations. As a resu It of this pu blicity, a small committee was formed. Each member has spent a considerable amount of his private time in this work. Not only have we had many discussions and even arguments with our own circle of professional colleagues, we have also spent some time in testing the practicality of theoretical principles. We all shared in the work of examining the information and working it all out on paper; but none of this would have come to fru ition without the support of the Institute and in particular from Cynthia Clark during her term of office as President. We owe a special debt of gratitude to David Treddinnick, who as Secretary of the Institute has quite enough to do, yet who always willingly made time available to bring the much valued 'photographer's point of view' into our discussions. Dr Peter Hansell made important contacts on our behalf when we were looking for a publisher and his sound advice has been of great benefit to the book at a critical time in its 'birth'. Mrs Sheila Carey, Director of Butterworths Ltd. and Chairperson of the medical division of the Publishers' Association, made our draft suggestions available to the members of her group and encouraged them to respond to our request for their views. We have incorporated many of their ideas into this publication. Mrs Carey's enthusiasm in support of this book has been consistent right from the beginning and is much appreciated. Mr P. M. Raphael of Peters and Peters, Solicitors, while he cautiously shares our view that the more people know about the laws of copyright the more carefu I they may be, nevertheless supports our suggestion that all serious problems of copyright should be dealt with by a specialist within the legal profession. His advice is highly valued. For the past few years, the meetings of the editorial subcommittee which produced this book were held at St Bartholomew's Hospital and we are particularly grateful to Peter Cull and his staff for providing hospitality. ix

9 CHARTS & GRAPHS Colin Cheeseman, Head of BBC-TV Graphics Department, and his staff offered a great deal of useful information and we are very grateful for the amount of time they gave to dealing with our questions. Finally I would like to acknowledge the personal support of Professor James Calnan of the Royal Postgraduate Medical School who has spent many years fighting for better standards in the audio-visual presentation of medical subjects. Professor Calnan actively contributed to the setting up of a small research fund to help provide materials for the study of graphic standards and their application in teaching and publication. Doig Simmonds~Editor x

10 Introduction This book has been compiled by professional members of the Institute of Medical and Biological Illustration. It is intended as a guide for persons preparing charts and graphs for publication or teaching slides by listing and describing some of the major limitations which must be observed if the visual presentation of data is to be legible and easily comprehended. The application of standards to the production of medical and biological graphics is long overdue and it is hoped that this book will not only help the amateur who is preparing his or her own illustrations, but that it will also serve as a reminder to the professional illustrator. We hope also that the publication of these standards might encourage the editors of journals to standardize on their requirements for contributors. The instructions contained in a large proportion of journals are often jmprecise and confusing. All illustrations need a structure of some kind to aid comprehension of data. Emphasis may be given to certain elements at the drawing stage and some suggestions for these will be mentioned where they have particular relevance. From the point of view of an audience it is well to remember that the eye of the onlooker is in constant motion and desires to select a prime point from which to begin an ordered and interesting journey. If this initial and fleeting moment, in which the eye 'questions' the object is lost the data or information may be shunned for ever as being boring. Good design aids the selection of a prime point and assists the journey all the way to its conclusion. Even tables can be made interesting by applying some of the principles described in this book. An illegible or badly designed illustration antagonizes the reader or viewer and can thus be a serious disadvantage to its author. A bad reputation is always hard to lose. It is most important to realize right from the start that legibility in one form does not automatically imply legibility in another. A reader may take as much time as he or she likes when reading a book or journal, but the information at a lecture is dispensed by the lecturer at a speed not necessarily suited to the audience orthe prevailing projection conditions. There are also other factors to be considered: whereas tables are often thought of as being the most accurate way of presenting data for publication, they are usually a visual bore when shown on the screen. It is most important therefore to give serious thought to the function of an illustration if the author is interested in his or her reputation, so that 'switching off effects can be avoided and the reputation protected. xi

11 CHARTS & GRAPHS Some of the standards suggested in this book are simple and straightforward. Most professional illustrators for example know that the capital letter height of any lettering being used must not be smaller than 1 /40th of the overall long dimension of the illustration if screen legibility is to be guaranteed when making slides. The same standard can also be applied to drawing for publication, but this is more complicated to define as much depends on whether the books and journals are printed in two columns or not. On questions of style, however, a great deal of controversy still exists. For instance, should scale index marks on graph axes point inwards or outwards? This and similar questions will never have unanimous answers. All that the authors of this book can do is to point out the advantages and disadvantages in any kind of style, and encourage our readers to find their own particu lar solutions to their own particu lar problems. The committee, formed by the Institute of Medical and Biological Illustration to devise this book on standards, consisted of one photographer, three artists and one typographer. Each one of us has, however, drawn heavily on the advice of our colleagues both within our profession and from the clients who use our services, and to them we owe a great debt of gratitude. These standards will provide the reader with a set of useful tools, but they cannot be absolute and will change as new techniques arise. D. Simmonds (Chairman) Photograph ( D. Simmonds xii