Against my better judgment, I recently engaged in a conversation about the ‘Law of Purchase Duplication’ with a young marketer. He seemed quite convinced that he was delivering a groundbreaking insight to a marketing dinosaur.
In essence, the law argues that the larger a brand’s market penetration, the more likely a consumer is to purchase alternative brands within the same category. Smaller brands, on the other hand, struggle with loyalty, relying primarily on occasional or incidental purchases when they fall within a larger brand’s ecosystem.
This concept, while not new, remains fundamental to understanding brand dynamics in the marketplace.
Back in the day, we referred to it as the purchaser’s ‘acceptable pool of brands.’
This young hot shot expanded on the advantages of being the dominant brand, and how it becomes self-sustaining through positioning, weight and quality of advertising, brand salience, product accessibility, and consumer perception. While this may all be true, the notion of it being ‘self-fulfilling’ is a step too far.
The reality is that maintaining market dominance requires constant effort and adaptation to changing consumer preferences and market conditions.
During our discussion, the topic of brand loyalty surfaced, leading to several useful questions about what brand loyalty truly means in today’s fast moving consumer markets:
- Does it mean that no other brand will ever be purchased under any circumstances?
- Does it only matter when a preferred brand is unavailable?
- Is there a sliding scale of brand loyalty that correlates to price differences?
- How does this law of duplication apply to sub-categories within the same brand?
- What are the varying impacts of demographics and psychographics of consumers?
- Could brand loyalty simply be a combination of awareness and preference, disconnected from actual purchasing behaviour in-store?
These questions highlight the complexity of consumer brand loyalty and the need for an understanding of the nuanced drivers of consumer behaviour in every market.
Over the years, I’ve been intimately involved with several instances where this so-called ‘Duplication of Purchase Law’ played out in real-world brand battles:
Meadow Lea Vs all comers. The rapid ascent of Meadow Lea margarine in the late 70s and early 80s was astonishing. The brand evolved from one of many competitors to a market leader, at its peak dominating with three times the market share of its nearest rival. Although it was driven by exceptional advertising, there were several alternative brands consumers could have turned to. However, consistent availability, competitive pricing, and in-store sampling helped cement its position. These instore marketing activities supported the brand advertising that built long term brand salience and loyalty.
Yoplait Vs Ski. The yogurt wars between Yoplait and Ski during the 80s and 90s are another example. Yoplait initiated huge market growth by making yogurt mainstream when it launched. This left Ski, the previous leader, floundering and scrambling to recover. Both brands became largely interchangeable despite product differentiation. Yoplait strawberry was an acceptable alternative to Ski strawberry, and vice versa. However, this dynamic didn’t extend evenly across other flavour categories or packaging formats. If Ski strawberry was unavailable, Yoplait strawberry was more likely to be purchased than an alternative ski flavour. These inconsistencies across the product categories and pack sizes, highlighted how nuanced and context-specific the Duplication of Purchase Law can be.
Having reliable data from the likes of Ehrenberg-Bass provides the statistical credibility necessary to sell what to date have been qualitatively understood wisdom, to the boardroom. However, it’s crucial to remember that this qualitative wisdom, built over time, should never be discarded or obscured by academic multi-syllable descriptions or management jargon. One-dimensional data cannot replace the wisdom accumulated by thoughtful marketers over time.
