Editor’s Note:
In 1979,Harvard Business Review
published “How Competitive Forces Shape Strategy” by a young economist and associate professor, Michael E. Porter. It was his first HBR article,
and it started a revolution in the strategy field. In
subsequent decades, Porter has brought his signature economic rigor to the study of competi-
tive strategy for corporations, regions, nations,
and, more recently, health care and philanthropy.
“Porter’s five forces” have shaped a generation of
academic research and business practice. With
prodding and assistance from Harvard Business
School Professor Jan Rivkin and longtime colleague Joan Magretta, Porter here reaffirms, up-
dates, and extends the classic work. He also addresses common misunderstandings, provides
practical guidance for users of the framework,
and offers a deeper view of its implications for
strategy today.