Understanding the Fundamentals of Epidemiology

an evolving text



Victor J. Schoenbach, Ph.D.


Wayne D. Rosamond, Ph.D.


Department of Epidemiology

School of Public Health

University of North Carolina at Chapel Hill

Fall 2000 Edition


© 1999, 2000 Victor J. Schoenbach


Unless otherwise indicated, the text and diagrams in this work belong to the copyright owner above. For reprint permission (royalty-free for noncommercial use by nonprofit, accredited, educational organizations), please write to:


Victor J. Schoenbach, Ph.D.

Department of Epidemiology

University of North Carolina

School of Public Health

Chapel Hill, NC 27599-7435 USA


Permission to reprint material copyrighted by others and used here by their permission must be obtained directly from them.

August 1999

Chapel Hill, North Carolina



Introductory epidemiology courses are often referred to as "methods" courses, and many students come to them hoping to learn the methods that have made epidemiology so important. Certainly methods are an essential aspect of the field, and this text covers the usual complement. But especially for the newcomer, the critical need is to learn how epidemiologists think about health and the factors that affect it, and how epidemiologists approach studying them. Very few methods are unique to epidemiology. "Epidemiologic thinking" is its essence. Therefore, for me the central objective of an introductory course has been to explain the concepts and perspectives of the field.

For nearly 20 years I have had the privilege of teaching the introductory epidemiology course for epidemiology majors at the University of North Carolina School of Public Health and the special pleasure that derives from teaching students who have sought epidemiology out rather than come to learn it only as a school requirement. I have also had the honor of being entrusted by my colleagues with the responsibility for introducing our students to epidemiologic concepts and methods.

Over the years I have written out extensive lecture notes, initially in response to requests from course participants and subsequently to develop my own understanding. Not all course participants have appreciated them, but I have received sufficient positive feedback and expressions of interest from graduates who have gone on to teach their own epidemiology courses that I have decided to recast them as an "evolving text". I use the term "evolving" because I continue to clarify, develop, refine, correct, and, I hope, improve.

Regarding it as an evolving text is also my excuse for the fact that the material is not ready for formal publication. Moreover, unlike a published text, this volume does not claim to be authoritative nor even thoroughly proofread. As an evolving work, its further development has always taken priority over appearance and, it must be admitted, occasionally also over accuracy.*

Although the word processing is nearly all my own, the content is certainly not. Besides the extensive development and exposition of epidemiologic concepts and methods from courses and publications by others, I have had the good fortune to study with and learn from outstanding epidemiologists and biostatisticians, among them the late John Cassel, Gerardo Heiss, Barbara Hulka, Michel Ibrahim, Sherman James, Bert Kaplan, David Kleinbaum, Gary Koch, Lawrence Kupper, Hal Morgenstern, Abdel Omran, the late Ralph Patrick, Dana Quade, David Savitz, Carl Shy, the late Cecil Slome, H.A. Tyroler, and Edward Wagner.

My thinking and this text have also greatly benefited from interactions with other colleagues and teachers, co-instructors, teaching assistants, collaborators, associates, research staff, fellows, and students. I must particularly acknowledge the assistance of Charles Poole, who has generously shared his expertise with me through his advanced methods course and frequent consultations. He has even made the ultimate sacrifice reading this text and sitting through my lectures! The content (errors excepted!) and to some extent the exposition, therefore, represent the knowledge, ideas, examples, and teaching skills of many people, to a much greater extent than the specific attributions, citations and acknowledgements would indicate.

Acknowledgements are of greater interest to authors than to readers, and I ask your forgiveness for including several more. I received my own introduction to epidemiology from the late John Cassel -- intellectual pioneer, inspiring lecturer, and humanist -- and Bert Kaplan -- quintessential scholar, supporter, and friend, whose colleagueship, breadth of knowledge, depth of wisdom, dedication to the ideals of the academy, and personal warmth have enriched the lives of so many. I would also like to express my gratitude to colleagues, staff, secretaries (especially Pat Taylor, Edna Mackinnon Lennon, and Virginia Reid), students, administrators, and family for inspiration, stimulation, feedback, opportunity, advice, guidance, commitment, counseling, assistance, support, affection, and a good deal more.

Enjoy Epidemiology!


Victor J. Schoenbach

Chapel Hill, North Carolina


August 17, 1999

Postscript: After the 20th anniversary edition of EPID 168 ("Fundamentals of epidemiology"), my teaching responsibilities have changed to its sister course, EPID 160 ("Principles of epidemiology"). EPID 160 serves as the basic introductory course for all students, graduate and undergraduate, who are not majoring in epidemiology. Thus its audience is much more diverse in both interests and preparation. Time will tell if I am able to continue to refine the Evolving Text, but if so it will begin to move in the direction of making it more suitable for a general - and international - readership. I have been gratified by the expressions of interest in it in its present form and hope that it will continue to be of use to others.

March 9, 2001.


* Important errata, as I learn about them, are posted at http://www.epidemiolog.net/.


Last modified 3/13/2001, 5/21/2001 by Victor J. Schoenbach