Intention-Behaviour Gap

Why this matters for your decision

Many plans for products, tariffs and prices are based on stated intention: "How likely are you to sign up for this offer?" Research shows that this intention explains only part of later behaviour. Sheeran and Webb (2016) summarise that intentions are acted upon in about half of all cases. Conner and Norman (2022) report that intentions explain 18 to 23% of the variance in behaviour.

A finding by Webb and Sheeran (2006) is particularly relevant for companies. In a meta-analysis of 47 experiments, intention was deliberately changed. A medium-to-large change in intention (d = 0.66) led to only a small-to-medium change in behaviour (d = 0.36). So when a new message or a new concept clearly increases stated intention, behaviour usually grows to a lesser extent.

For a decision, this means: a lead in stated intention is an indication, but not yet a reliable assumption for demand or the business case.

How the gap arises

Research names several reasons. Intentions are often weak or provisional. In everyday life they compete with other goals. The effort of signing up is underestimated. And at the moment of decision, price and alternatives come to the fore, which appear only in the abstract in a survey. Strong, stable intentions are more likely to be acted upon than weak ones, but even they are not always.

Example

An online retailer asks regular customers whether they would sign up for an annual subscription for free delivery. A large share answers "probably yes". In the behavioural test, people see a realistic offer page with an annual price and a sign-up path. The share who make the last binding click before the reveal is clearly below the share of positive answers. For planning the launch, this second value is the more reliable assumption; the survey supplies the reasons for hesitation.

How it differs

Say-Do Gap is the broader term, common in marketing, for any gap between what people state and what they do. The intention-behaviour gap is its psychological core: the gap between intention and action.

Hypothetical bias describes a related but different effect: stated willingness to pay is higher than the real one. The attitude-behaviour gap starts earlier, with an attitude, for example towards sustainability, that does not lead to a purchase.

Limitations

The figures cited come mainly from health and social psychology, not only from purchase decisions. They show that the gap is robust, not how large it is for a specific tariff or product. That can only be measured for the decision in question.

A behavioural test also measures one specific action: measured purchase or sign-up intent at the moment of the offer. It does not show whether someone later actually pays, stays or buys again. Horizon measures this action on realistic offers, and nothing is sold.