FROM THE ORIGINAL BOOK GLOSSARY
Drift is a divergence that persists over a defined time horizon between the state toward which a business is evolving and the conditions established for sustaining the products or services and the economic model it intends to maintain.
It does not mean failure, nor does every unfavorable movement in a metric constitute Drift. A deliberate change in strategy changes the conditions against which Drift must be observed.
THINK ABOUT IT
Is this still the business we meant to build?
A restaurant can change its pace, menu and atmosphere one decision at a time. Drift asks whether those changes are moving it away from the experience it set out to offer.