Evidence · Claim check
Does the duplication of purchase law hold?
Well establishedYes, in consumer markets. Across many categories and countries, a brand shares its buyers with each competitor roughly in proportion to that competitor's penetration, rather than keeping them in isolated segments. The pattern is weaker in strongly partitioned categories, single-brand subscriptions and some niche online brands, and in B2B markets it has barely been tested.
The claim
A brand's customers also buy competing brands, and they do so in proportion to those competitors' penetration (size); customer sharing is not split into isolated segments.
Why it could be true: Brand choice is driven mainly by physical and mental availability rather than exclusive preference. Category buyers therefore rotate across a repertoire of brands, and bigger brands appear in more of those repertoires.
Verdict by context
- Consumer markets: Well established, high certainty. The pattern is weaker in strongly partitioned markets, where a category splits into functional subgroups, and in subscription models built around a single brand; niche online brands can deviate. Support comes from highly varied data (packaged goods, wine, sport, politics and physical activity in the UK, US, Australia, China and Spain) and from the Ehrenberg-Bass Institute plus four independent teams.
- B2B markets: Too little evidence, very low certainty. The only direct B2B evidence among the studies reviewed here is one book based on Ehrenberg-Bass Institute data. The direction is plausible, but the strength of the pattern has not been measured.
The evidence
| Role | Finding | Study | Design |
|---|---|---|---|
| Supports | A canonical review of duplication and double jeopardy patterns across categories, with duplication tables that synthesise many consumer panels.[1] | Ehrenberg et al. (1990) | Review |
| Supports | A review of 50 years of Dirichlet model applications, including its predictions of how brands share buyers.[2] | Driesener & Rungie (2022) | Review |
| Supports | Double jeopardy and duplication of purchase extend to the US wine market, shown in duplication tables.[3] | Wilson & Winchester (2019) | Observational |
| Supports | The structure of the Australian wine market follows the duplication of purchase pattern.[4] | Cohen et al. (2012) | Observational |
| Supports | Duplication patterns also appear in how people split their time across physical activities, which carries the pattern beyond brand purchases.[5] | Wilson et al. (2019) | Observational |
| Supports | An independent team finds the double jeopardy pattern in Chinese services, with satisfaction acting as a mediator.[6] | Yang et al. (2005) | Observational |
| Supports | An independent team confirms the double jeopardy effect in Spanish panel data using a discrete choice model, a different method.[7] | Labeaga et al. (2007) | Model |
| Supports | An independent team finds double jeopardy among Australian sports brands.[8] | Doyle et al. (2012) | Observational |
| Sets limits | Tracked over time, online brands can show negative double jeopardy, a boundary condition for niche online brands.[9] | Kucuk (2010) | Longitudinal observational |
| Sets limits | An independent team compares behavioural and attitudinal double jeopardy and finds that attitudes behave differently from purchases.[10] | Bandyopadhyay & Gupta (2004) | Observational |
| Supports | A chapter on how B2B brands share clients. The book is not peer reviewed and draws on Ehrenberg-Bass Institute data.[11] | Romaniuk et al. (2021) | Book |
What this does not say
- It does not address whether positioning can reduce the overlap. The law describes how much overlap there is, not what changes it.
- It does not cover overlap between product categories, only between brands within a category.
References
- Andrew S. C. Ehrenberg, Gerald J. Goodhardt, T. Patrick Barwise (1990). Double Jeopardy Revisited. Journal of Marketing.
- Carl Driesener, Cam Rungie (2022). The Dirichlet Model in Marketing. Journal of Consumer Behaviour.
- Damien Wilson, Maxwell Winchester (2019). Extending the double jeopardy and duplication of purchase laws to the wine market. International Journal of Wine Business Research.
- Justin Cohen, Larry Lockshin, Byron Sharp (2012). A better understanding of the structure of a wine market using the attribute of variety. International Journal of Business and Globalisation.
- Amy L. Wilson, Cathy Nguyen, Svetlana Bogomolova, Byron Sharp, Timothy Olds (2019). Analysing How Physical Activity Competes: A Cross-Disciplinary Application of the Duplication of Behaviour Law. International Journal of Behavioral Nutrition and Physical Activity.
- Zhilin Yang, Zili Bi, Nan Zhou (2005). The Double Jeopardy Phenomenon and the Mediating Effect of Brand Penetration between Advertising and Brand Loyalty. Journal of Advertising Research.
- José M. Labeaga, Nora Lado, Mercedes Martos-Partal (2007). Testing the Double Jeopardy Loyalty Effect Using Discrete Choice Models. FEDEA, Documento de Trabajo 2007-21.
- Jason P. Doyle, Kevin Filo, Heath McDonald, Daniel C. Funk (2012). Exploring sport brand double jeopardy: The link between team market share and attitudinal loyalty. Sport Management Review.
- S. Umit Kucuk (2010). Negative Double Jeopardy revisited: A longitudinal analysis. Journal of Brand Management.
- Subir Bandyopadhyay, Kaushik Gupta (2004). Comparing Double Jeopardy Effects at the Behavioral and Attitudinal Levels. Journal of Product & Brand Management.
- Jenni Romaniuk, John Dawes, Byron Sharp, Arry Tanusondjaja, Magda Nenycz-Thiel (2021). How B2B Brands Grow. Ehrenberg-Bass Institute / LinkedIn B2B Institute.
Bibliographic details only. Follow the DOI to read each study at its publisher.
Related topics
Claim check written by ScholarSignal. Last reviewed 2026-09-26.
Building on this evidence?
ScholarSignal checks a new research idea against the closest existing work and an editor rubric, and tells you whether the contribution is new enough for the journals you target.
Evaluate my idea for free