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Loyalty Is Everywhere, Growth Isn't. With Dr. Nicole Hartnett.

EP 194 · Apr 28, 2026 · 64 min · Marc & V

0:00 / 1:03:51

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Description

Picture a marketing world flipped upside down: Where heavy buyers aren't your golden goose, where loyalty programs might be missing the point, and where the brands you think are exceptional actually follow surprisingly predictable patterns. Dr. Nicole Hartnett, senior marketing scientist at the world-renowned Ehrenberg-Bass Institute, joins Marc and V to demolish some of marketing's most sacred assumptions with cold, hard data.

The Ehrenberg-Bass Institute is the world's largest centre for research into marketing and Dr. Nicole Hartnett has won the Market Research Society (MRS) Award for the best paper published by the International Journal of Market Research in 2022. Her groundbreaking research "When Brands Go Dark" analyzed 365 US brands from 22 consumer goods categories that stopped advertising for at least one year, revealing that brands experienced average sales declines of 16% after the first year, 25% after two years, and 36% after three years.

In this episode, you'll hear Nicole explain why most customer bases are dominated by light buyers who contribute roughly 40-50% of sales, how the Double Jeopardy law proves that big brands don't just have more customers but also slightly more loyal ones, and why mental and physical availability matter more than differentiation. She breaks down the difference between repertoire and subscription markets, reveals why advertising effects are "spread out really thinly over time" like "hitting them with a feather," and shares the surprising patterns that hold true across everything from coffee purchases to B2B software.

This isn't theoretical—it's the kind of evidence-based marketing science that's transformed how the world's biggest brands actually grow, backed by decades of empirical research that challenges everything you thought you knew about customer loyalty and brand building.

Timestamps

00:00: Welcome and introducing Dr. Nicole Hartnett from Ehrenberg-Bass Institute

03:04: Defining repertoire vs subscription markets and loyalty patterns

08:40: The Double Jeopardy law explained - why smaller brands suffer twice

16:16: Light vs heavy buyers - who really drives brand growth?

26:50: Mental and physical availability as growth drivers

29:30: Reach vs frequency - the advertising convex response function

36:45: "When Brands Go Dark" research findings on advertising cessation

46:00: What makes great advertising - Old Spice campaign breakdown

54:12: Distinctive assets and brand identity management systems

References

Primary Source

Hartnett, N., Gelzinis, A., Beal, V., Kennedy, R., & Sharp, B. (2021). When brands go dark: Examining sales trends when brands stop broad-reach advertising for long periods. Journal of Advertising Research, 61(3), 247-259.

Referenced Frameworks / Research

Sharp, B. (2010). How Brands Grow: What marketers don't know. Oxford University Press.

Sharp, B., & Romaniuk, J. (2021). How Brands Grow Part 2. Oxford University Press.

Romaniuk, J. Building Distinctive Brand Assets. Oxford University Press.

Sharp, B. (2018). Marketing: Theory, Evidence, Practice (2nd ed.). Oxford University Press.

Referenced in Discussion

Phua, P., Hartnett, N., Beal, V., Trinh, G., & Kennedy, R. (2023). When Brands Go Dark: A Replication and Extension: Examining Market Share of Brands That Stop Advertising for a Year or Longer. Journal of Advertising Research, 63(2), 172-184.

Nicole on LinkedIn https://www.linkedin.com/in/nicole-hartnett/

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Transcript

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SPEAKER_00: Welcome to the Sleeping Barber Podcast.

SPEAKER_05: Four years and 182 episodes ago, we published our most popular interview to date with Dr. Nicole Hardin of the Ehrenberg Bass Institute.

SPEAKER_04: We recorded this before we did postpods, before the barbers brief and sharp cuts, back when we were really just a couple of guys as confused by marketing laws as we were how to record a podcast. Four years on, the laws still hold, and today we're rebooting the original with a fresh postpod dropping this Thursday.