Context

Drucker drew a foundational distinction between efficiency (optimising how work is done) and effectiveness (choosing the right work to do at all). He argued that executives who focus only on efficiency risk optimising the wrong activities entirely. This formulation appeared in progressively sharper form across his 1963 HBR article "Managing for Business Effectiveness," a 1965 University of Toronto lecture, and this 1974 book. Quote Investigator confirms Drucker as the primary originator of this modern phrasing.