In short: the linear AIDA funnel, theorized in 1898, has never received empirical validation as a description of real purchasing behavior. Evidence-based research shows that consumers do not follow sequential paths but oscillate in an explore-evaluate loop (Google Messy Middle, 2020), that brand growth depends on reach and mental availability (Ehrenberg-Bass), and that the 60/40 long/short term split beats the performance-only funnel (Binet & Field, IPA).
- Binet & Field (IPA): the study The Long and the Short of It demonstrates that 60% brand building + 40% activation produces maximum ROI, not the full-funnel performance approach
- Ehrenberg-Bass + NBD-Dirichlet: purchasing behavior follows non-linear statistical laws (Double Jeopardy, Duplication of Purchase), not sequential funnels
- Google Messy Middle (2020): analysis of thousands of real journeys confirms the absence of linearity — consumers loop between exploration and evaluation
- BCG 2025: brands that abandon the linear funnel record revenue growth +60% compared to those who persist with the AIDA model
What a marketing funnel is
A marketing funnel is a conceptual model that represents the consumer's journey from awareness to conversion as a linear, funnel-shaped sequence: many potential customers enter at the top (awareness), few reach the bottom (purchase). The original formulation dates back to 1898, when American advertiser Elias St. Elmo Lewis proposed the AIDA model: Awareness, Interest, Desire, Action. Every step of the funnel presupposes the previous one, and every consumer is treated as a rational decision-maker traversing discrete mental states.
Over 126 years the model has been reformulated dozens of times — TOFU/MOFU/BOFU, Avinash Kaushik's See/Think/Do/Care, the pirate funnel (AAARRR), multi-stage consideration sets — without ever receiving robust scientific validation. It remains today the foundation on which consultants and agencies sell digital strategies, but its survival depends on commercial convenience (easy to explain, easy to sell), not on empirical evidence.
Why the AIDA model is obsolete
AIDA was conceived before the internet, before smartphones, before social media, online reviews, price comparators, or programmatic advertising. Cognitive psychology didn't even exist as a discipline. The question no one ever asks is a simple one: has AIDA ever been empirically validated?
The answer is no. In 126 years the linear funnel has never received robust scientific validation as an accurate description of real purchasing behavior. It has remained what it was: a useful metaphor to simplify a complex phenomenon. The problem is that the metaphor became dogma, and the dogma became a multibillion-dollar industry that perpetuates itself regardless of results.
Varnali (2019), in a study published in The Service Industries Journal, showed that customer journeys satisfy the formal definition of a non-linear complex system: sensitive to initial conditions, with multiple feedback loops, unpredictable emergent behavior, properties that cannot be deduced from the sum of the parts. Even knowing every touchpoint perfectly, it is impossible to predict the overall path. AIDA violates these properties at the root.
What science says about the consumer decision journey
Evidence-based research over the last 15 years has produced three converging bodies of work that dismantle the linear funnel from the foundations.
Ehrenberg-Bass Institute — the most important academic marketing research centre, based at the University of South Australia — has documented that purchasing behavior follows stable statistical laws, not psychological sequences. The two most important: the Double Jeopardy Law (smaller brands have fewer customers AND those customers buy less often) and the Duplication of Purchase Law (the overlap of customers between competing brands is proportional to their market share). These laws operate independently of consumers' "position in the funnel".
The underlying mathematical model is the NBD-Dirichlet, formulated by Goodhardt, Ehrenberg and Chatfield: a non-linear statistical framework that precisely predicts market shares, purchase frequencies and brand penetration without resorting to any funnel concept. The strategic consequence, theorized by Byron Sharp in How Brands Grow (2010), is that brands grow by winning over light buyers (occasional, non-loyal consumers) through mental availability (brand memorability) and physical availability (presence at points of purchase). Neither of these two drivers requires a funnel.
Les Binet and Peter Field, in a series of studies commissioned by the IPA (Institute of Practitioners in Advertising) and collected in The Long and the Short of It (2013, 2017, 2024), analyzed hundreds of IPA Effectiveness Awards campaigns. The key finding: the optimal budget allocation is 60% brand building / 40% activation. Brand-heavy campaigns produce the greatest ROI in the long term (3+ years), while performance activation has short effects and rapid decay. The linear funnel, by concentrating the budget on the phases "closest to conversion", systematically underinvests in the brand — and produces sub-optimal growth.
Google's Messy Middle model
In 2020 Alistair Rennie and Jonny Protheroe, researchers at Google, published Decoding Decisions: Making Sense of the Messy Middle. The study analyzes thousands of real purchase journeys and arrives at a clear conclusion: consumers do not traverse a funnel. They oscillate in a chaotic, potentially infinite loop between two cognitive modes — exploration (expansion of considered options) and evaluation (narrowing down).
There is no sequence. There is no predictable direction. A consumer may explore for weeks, narrow down to two options, then re-expand to ten after reading a negative review. The path is not funnel-shaped — it is labyrinth-shaped. Google identified six cognitive biases that drive decisions in the loop: category heuristics, power of now, social proof, scarcity bias, authority bias, power of free. These biases activate simultaneously, in varying order, with different weights for every consumer and product category.
BCG, in January 2025, published the report Move Beyond the Linear Funnel, identifying four digital behaviors — streaming, scrolling, searching, shopping ("4S") — that shatter any residual claim to linearity. Companies that have embraced artificial intelligence to manage this complexity recorded revenue growth 60% higher than those who persist with the funnel.
What actually works (Sharp/Ehrenberg-Bass)
The evidence converges on one principle: to grow, a brand must maximize the probability of being chosen when the need arises, in every relevant purchase category, for the largest number of consumers possible. Byron Sharp calls this mental availability — the ease with which the brand is brought to mind in buying situations. It is not built with email sequences or retargeting. It is built with broad and repeated reach, distinctive brand assets (recognizable logo, colours, pack, mascot, jingle) and presence at the Category Entry Points (the situations that trigger purchase).
The most rigorous operational framework is that of Binet & Field:
- 60% brand building: emotional, high-reach campaigns, focused on distinctiveness and memorability. Horizon 1-3 years. KPIs: penetration, mental availability, share of voice.
- 40% activation: rational campaigns targeted at those with active purchase intent. Horizon 1-12 weeks. KPIs: conversions, ROAS.
- Never just activation: without brand building, activation decays rapidly because there is no mental availability to convert. This is the failing model of DTC brands (Allbirds, Warby Parker) that have lost hundreds of millions by relying solely on performance.
Comparative table: traditional funnel vs evidence-based model
How to reallocate budget without a funnel
For SMEs with limited budgets, translating the evidence-based framework into concrete actions requires 5 progressive moves:
- Shift 60% of the budget to brand building. High-reach campaigns (video, display, YouTube, radio, OOH depending on budget), with an emotional message focused on Category Entry Points — the concrete situations where the product becomes relevant. KPIs: unique reach, frequency 1+, aided recall.
- Invest in distinctive brand assets. Logo, colours, pack, mascot, jingle: coherent sensory elements that the consumer can recognize in 0.5 seconds. Romaniuk (2018) shows that brands with strong distinctive assets have significantly higher spontaneous conversion in SERPs and on shelves.
- Keep 40% activation but rationalize it. Google Ads on commercial-intent queries, retargeting with a low frequency cap (max 4 exposures), email to warm opt-in lists. No more than 3 nurturing steps — long sequences have a doubled unsubscribe rate (MailerLite 2025).
- Measure reach and penetration, not just conversions. The key KPI is not step-by-step conversion rate (statistically insignificant at SME volumes, Larsen et al. 2024), but the LTV/CAC ≥ 3 ratio, penetration (% of the category buying at least once a year) and share of voice.
- Feed structured word-of-mouth. Nielsen (2021) confirms that 88% of consumers trust personal recommendations more than any other channel. Referral programmes, verified reviews, local events, partnerships: systems that facilitate word-of-mouth produce lower CAC than any digital funnel.
The operational synthesis: funnels attempt to mechanize a process — the purchase decision — that is intrinsically human, chaotic and social. The evidence-based alternatives (Sharp, Ehrenberg-Bass, Binet & Field) are not cheaper, but they are aligned with the way people actually decide and predict outcomes with validated statistical models.
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Frequently Asked Questions
Why are marketing funnels a myth?
The linear AIDA funnel, formulated in 1898, has never received scientific validation as an accurate description of purchasing behavior. Evidence-based research (Ehrenberg-Bass Institute, Byron Sharp, Binet & Field, Google Messy Middle) shows that consumers do not follow sequential paths but oscillate in non-linear loops. The funnel survives for commercial convenience — it is easy to explain and sell — not on scientific merit.
What does science say about the consumer decision journey?
Science describes the consumer decision journey as a non-linear complex system (Varnali, 2019) governed by stable statistical laws: Double Jeopardy, Duplication of Purchase Law, NBD-Dirichlet. Purchasing behavior follows mathematically validated patterns based on mental availability and penetration, not on sequential psychological states. Brands grow by winning light buyers through broad reach and distinctive assets, not by nurturing leads through funnels.
What is Google's Messy Middle?
The messy middle is the decision journey model proposed by Google in 2020 (Rennie & Protheroe). It replaces the funnel with a chaotic loop between two cognitive modes: exploration (expansion of considered options) and evaluation (narrowing down). The consumer oscillates back and forth without a predictable sequence, driven by six cognitive biases (category heuristics, power of now, social proof, scarcity, authority, power of free) that activate simultaneously.
What is an alternative model to the funnel?
The most rigorous model is that of Binet & Field (IPA): allocate 60% of the budget to brand building (emotional high-reach campaigns, 1-3 year horizon) and 40% to activation (performance campaigns, 1-12 week horizon). Combined with the Ehrenberg-Bass principles (mental & physical availability, Category Entry Points, distinctive brand assets) and McKinsey's Community Flywheel, it produces documented growth across the 128 IPA Effectiveness Awards case studies.
Can the funnel ever be useful?
The funnel works as an internal visualization tool in specific contexts: e-commerce with very high volumes (where A/B testing becomes statistically valid), digital products with high margins and short cycles, companies with an already established brand. The problem is not the funnel as a conceptual map, but the funnel as a universal strategy sold to SMEs with 500 visitors per month, where step-by-step optimizations are mathematically meaningless (Larsen et al., 2024).
Sources and References
- Binet, L. & Field, P. — The Long and the Short of It: Balancing Short and Long-Term Marketing Strategies. IPA, 2013 (updated 2017, 2024)
- Rennie, A. & Protheroe, J. — Decoding Decisions: Making Sense of the Messy Middle. Think with Google, 2020
- Ehrenberg-Bass Institute for Marketing Science — University of South Australia (Sharp, Romaniuk, Kennedy)
- Journal of Advertising Research — ARF (Advertising Research Foundation)
- Journal of Marketing — American Marketing Association
- BCG — Move Beyond the Linear Funnel, January 2025
- Varnali, K. — Understanding customer journey from the lenses of complexity theory. The Service Industries Journal, 2019
- Nielsen — Trust in Advertising Study, 2021
- McKinsey — The Community Flywheel, 2022
