Understanding Double Jeopardy
Double jeopardy was popularized in marketing by the British academic Andrew Ehrenberg. It boils down to the fact that a small-share brand is penalized twice—it has fewer buyers than a large-share brand, and they buy less frequently. As a consequence, most of a brand’s market share is explained by its market penetration and the size of its customer base, rather than by customers’ repeat purchases. Implicit is the assumption that brands are substitutable and have target segments in common. It is, in fact, most often observed with weakly differentiated brands targeting the same group of people. Exceptions are highly differentiated niche brands that thrive on small shares and high loyalty and seasonal brands that offer unique value and tally cluster purchases in short periods of time.
One implication drawn by double jeopardy proponents is that marketers seeking growth should focus on increasing the size of the customer base rather than on deepening the loyalty of existing customers. Critics of double jeopardy question how inevitable it is and see other implications for marketers. For example, they view new or established brands with a new positioning or message as differentiated enough to avoid double jeopardy’s predicted results.
Sources: John Scriven and Gerald Goodhardt, “The Ehrenberg Legacy,” Journal of Advertising Research, June 2012, pp. 198-202; Byron Sharp, How Brands Grow: What Marketers Don’t Know (Melbourne, Australia: Oxford University Press, 2010); Nigel Hollis, “The Jeopardy in Double Jeopardy,” www.millwardbrown.com, September 2, 2009; Andrew Ehrenberg and Gerald Goodhardt, “Double Jeopardy Revisited, Again,” Marketing Research, 2002. See also Andrew Ehrenberg: A Tribute (19262010), Special Section, Journal of Advertising Research 52 (June 2012).