Welcome to the first Sharp Cut from The Sleeping Barber Podcast — a tighter, opinion-led format designed to challenge marketing’s most persistent assumptions. In this episode, Vassilis and Marc take on one of the industry’s most widely accepted beliefs: one-to-one personalization.

Despite overwhelming surveys claiming consumers want personalization and businesses need it, the evidence tells a very different story. Drawing on peer-reviewed research from Ehrenberg-Bass, MIT, Melbourne Business School, Nielsen, and the Journal of Advertising Research, this Sharp Cut separates belief from evidence.

They unpack why personalization systems are built on inaccurate data, why targeting errors compound rather than optimize, why click-through rates are meaningless, and how narrow targeting actively undermines growth by excluding future buyers.

Most importantly, they outline what actually works: reach, creative quality, mental availability, contextual relevance, and proper experimentation.If you care about effectiveness over mythology, this episode is for you.

Chapters:

00:00 - Introduction

04:13 - Beliefs vs. Evidence

07:48 - The Targeting Effectiveness Evidence

11:07 - The Compound Problem

12:54 - The Measurement Illusion

14:47 - The Hidden cost of Narrow Targeting

17:21 - What Actually Works

20:00 - Our Final TakeKey

Key Takeaways

1. Personalization is widely believed, not well proven. Most supporting stats come from surveys and vendor case studies, not controlled experiments.
2. Data accuracy is poor. Identity and attribute targeting accuracy often ranges between 32–69%, with many segments no better than a coin flip.
3. Targeting errors compound. Stacking multiple “precise” attributes multiplies mistakes, not accuracy—often reaching less than 15% of the intended audience.
4. Third-party targeting performs no better than random. This holds true in both B2C and B2B contexts, even for senior decision-makers.CTR is a vanity metric.
5. Studies show click-through rates have near-zero correlation with brand outcomes or ROI.
6. Narrow targeting hurts growth. It focuses spend on the ~5% in-market while excluding the 95% who drive future demand.

What works instead:

1. Reach over precision
2. Context over profile
3. First-party data for retention, not acquisition
4. Creative as the real targeting lever
5. Measurement tied to business outcomes
6. Controlled testing with holdouts

Links:

The value of getting personalization right—or wrong—is multiplying. https://www.mckinsey.com/capabilities/growth-marketing-and-sales/our-insights/the-value-of-getting-personalization-right-or-wrong-is-multiplying

Artist sells invisible sculpture—Adtech sells the same thing. Forbes. https://www.forbes.com/sites/augustinefou/2021/06/03/artist-sells-invisible-sculptureadtech-sells-the-same-thing/

Yeo, T. E. D., Chu, T. H., & Li, Q. (2025). How persuasive is personalized advertising? A meta-analytic review of experimental evidence of the effects of personalization on ad effectiveness. Journal of Advertising Research, 65(4), 616–631. https://doi.org/10.1080/00218499.2025.2467763

Neumann, N., Tucker, C. E., Subramanyam, K., & Marshall, J. (2023). Is first- or third-party audience data more effective for reaching the ‘right’ customers? Quantitative Marketing and Economics, 21(4), 519–571. https://doi.org/10.1007/s11142-023-09796-w

Dyson, P. (2021, July 14). The advertising multipliers that matter are not what marketers think. Kantar. https://www.kantar.com/inspiration/advertising-media/the-advertising-multipliers-that-matter-are-not-what-marketers-think

East, R., Romaniuk, J., Chowdhury, T., & Uncles, M. (2023). The fallacy of the retention economy. International Journal of Market Research, 65(4), 415–431. https://doi.org/10.1177/14707853231174549

WARC. (2023). The multiplier effect report: How to maximize the impact of your advertising.