ditor’s Note:
In 1979,
Harvard Business Review
published “How Competitive Forces Shape Strat-
egy” by a young economist and associate profes-
sor, 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 sig-
nature 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 col-
league Joan Magretta, Porter here reaffirms, up-
dates, and extends the classic work. He also ad-
dresses common misunderstandings, provides
practical guidance for users of the framework,
and offers a deeper view of its implications for
strategy today.