Preface to the Second Edition
Biostatistical aspects are receiving increased emphasis in medical books, medical journals, and pharmaceutical literature, yet appreciation of biostatistical methods as a medical tool is lacking. This book arises from the desire to help biostatistics earn its rightful place as a medical, rather than a mathematical, subject. Medical and health professionals may then perceive this as their own, instead of an alien, discipline, A book that effectively focuses on the statistical aspects of medicine with a medical perspective is clearly needed.
Variation is an essential, and perhaps the most enjoyable, aspect of life. But consequent uncertainties are profound. Thus, methods are needed to measure the magnitude of uncertainties and to minimize their impact on decisions. Biostatistics is the science of management of uncertainties in health and medicine. Beginning with this premise, this book provides a new orientation to the subject. This theme is kept alive throughout the text. I have tried to demonstrate that biostatistics is not just statistics applied to medicine and health sciences but is a two-step further that provides tools to manage some aspects of medical uncertainties.
The primary target audience is students, researchers, and professionals of medicine and health. These include clinicians who deal with medical uncertainties in managing patients and want to practice evidence-based medicine; research workers who design and conduct empirical investigations to advance the knowledge, including those in pharmaceutical industry who search new regimens that are safer and more effective yet less expensive and more convenient; and health administrators who are concerned with epidemiological aspects of health and disease.
Even though the text is tilted to the view-point of medical and health professionals, the contents are of sufficient interest to a practicing biostatistician and a student of biostatistics as well. They may find some sections very revealing, particularly the heuristic explanations provided for various statistical methods. Emphasis is on the concepts and interpretation rather than on theory or intricacies of the methods. Theoretical development is intentionally de-emphasized and applications increasingly emphasized. A large number of real-life examples are included that illustrate the method and explain the medical meaning of the results.
In the process of projecting biostatistics as a medical discipline, it is imperative to place less emphasis on mathematical aspects. But the essential algebra, which is needed to communicate and understand some statistical concepts, is not ignored. In fact, the second half of the book makes liberal use of notations. An attempt is made to strike an even balance. Medical and health professionals, who are generally not well trained in mathematics, may find the language and presentation very conducive. Equations and formulas are separately identified and manual calculation described for the fundamentals, but the emphasis is on use of computer for advanced calculations.
The text is fairly comprehensive and incorporates a large number of statistical concepts used in medicine and health. The contents are more than an introduction and less than an advanced treatise. References have been provided for further reading. A medical or a health professional should be able to plan and carry out an investigation by himself on the basis of this text and to intelligently seek the help of an expert biostatistician when needed. Medical laboratory professionals, scientists in basic medical sciences, epidemiologists, public health specialists, nutritionists, and others of health related disciplines may also find this volume useful. The text is expected to provide a good understanding of the statistical concepts required to critically examine medical literature. The material is suitable for use in preparation for professional examinations such as that for membership in the College of Physicians. The content is also broad enough to cover an undergraduate biostatistics course for medical and health science students.
Among the excellent reviews the first edition of the book received from across the world, the one most gratifying was that described it as ‘perhaps the most complete book on biostatistics’. This encouraged me to include further topics in second edition that a book of this nature ought to have but missed earlier so that it can really earn the distinction of the most comprehensive book on biostatistics. Thus, there is a full chapter now on clinimetrics and evidence-based medicine that includes various medical indexes and scoring systems. In place of sections, now there is a full chapter each on sampling methods, observational studies, laboratory experiments, clinical trials, logistic regression and survival analysis. Topics such as epistemic uncertainties, crossover designs, equivalence trials, equivalence tests, hazard functions, Mantel-Haenzel procedure, and log-rank test have been considerably expanded. In addition, topics such as levels of evidence, comparison of sensitivities and specificities, multilevel regression, and classification and regression trees have been introduced, albeit at elementary level. Sample size formulas have been included for relative risk, odds ratio and survival studies. A large number of new examples have been added. Now all examples are clearly demarcated.
Because of addition of large material and rearrangement, the number of chapter now is 21 instead of 14 earlier. The sequence of chapters may not look natural to statisticians because their thoughts follow mathematical continuum but may look natural to medical and health professionals whose biostatistics needs are for problem solving.
I am confident that the book would be found as the most comprehensive treatise on biostatistical methods. In the process, I realize I am undertaking the risk involved in including elementary and middle level discussion in the same book. I would be happy to get reactions.
Abhaya Indrayan
