Andrew Ehrenberg
Marketing scientist whose work on repeat buying underlies much of what is now taught about brand loyalty. He extended the double jeopardy pattern, first described by William McPhee in 1963, to brand purchasing, and formalised it in 1990 with Gerald Goodhardt and Patrick Barwise.
Who they are
Ehrenberg's approach was to look for regularities that hold across many products, markets and years before trying to explain them. His book-length statement is Repeat-Buying, first published in 1972 with a second edition in 1988. Byron Sharp's How Brands Grow is largely a retelling of the programme he started.
Key papers
Ehrenberg, A. S. C., Goodhardt, G. J., & Barwise, T. P. (1990). "Double jeopardy revisited." Journal of Marketing, 54(3), 82-91. doi:10.1177/002224299005400307.
Ehrenberg, A. S. C. (1972; 2nd ed. 1988). Repeat-Buying.
Key ideas
Small brands have fewer buyers who are also slightly less loyal. See Double Jeopardy.
Sources
- Ehrenberg, Goodhardt & Barwise (1990), Journal of Marketing, bibliographic record confirmed. Credit for the pattern to McPhee and the brand-purchasing extension to Ehrenberg follows the verification record behind How Brands Grow, 8 October 2026.