Sheeran & Webb (2016): The Intention-Behavior Gap
Sheeran and Webb's 2016 review in Social and Personality Psychology Compass summarised decades of evidence on the intention-behaviour gap: the reliable finding that intending to do something only weakly guarantees doing it. Across meta-analyses, intentions translate into action only around half the time, and experimentally boosting intentions produces much smaller changes in behaviour. Most failures come from 'inclined abstainers', people who genuinely intend to act but never start, get derailed, or fail to sustain the behaviour, which is a precise description of procrastination.
| Citation | Sheeran, P., & Webb, T. L. (2016). The intention-behavior gap. Social and Personality Psychology Compass, 10(9), 503–518. |
|---|---|
| Study type | Narrative review synthesising meta-analytic evidence |
| Key finding | Meta-analyses show roughly half of intentions are not enacted; medium-to-large changes in intention produce only small-to-medium changes in behaviour |
| Where the gap comes from | Failing to get started, getting derailed by habits and temptations, and failing to stay in pursuit; mostly among 'inclined abstainers' |
What the study found
The review pulls together the quantitative evidence: prospective studies find intenders act on their intentions only about half the time, and experimental work shows that even successfully changing people's intentions moves actual behaviour far less. Decomposing the gap, the authors show it is driven almost entirely by inclined abstainers, people with positive intentions who do not follow through, rather than by people acting without intending to. The follow-through failures sort into three problems: not initiating (forgetting, missing the moment, not feeling like it), getting derailed (habits, temptations, competing goals), and not sustaining effort. Intentions based on strong attitudes, formed with specific plans, and backed by self-monitoring are enacted far more often.
Why it matters
Procrastination lives inside this gap: by definition, the procrastinator intends to act and does not. The review explains why motivation-first advice fails, your intention is usually already fine, the machinery connecting it to action is what breaks, and it points at the fixes with the best evidence: implementation intentions that pre-decide when, where and how you will start, monitoring progress, and disrupting the cues that trigger derailing habits. It is the theoretical backbone for why planning the start beats resolving to try harder.
Caveats
As a review it inherits the limits of its inputs: much of the evidence concerns health behaviours like exercise and screening in Western samples, and behaviour is often self-reported. The 'about half' figure is an average across very different behaviours, one-off acts show smaller gaps than repeated ones. And explaining the gap is not the same as closing it: even the best gap-closing tools, like implementation intentions, produce moderate improvements, not certainty.
Peer-reviewed review in Social and Personality Psychology Compass by two leading researchers on goal pursuit. Verified via Crossref.
Related
Implementation Intentions, the main gap-closing toolGollwitzer & Sheeran's meta-analysis of if-then plans
Frequently asked questions
Why do I never do what I plan to do?
You are in good company: research finds intentions are acted on only about half the time. The failure usually is not weak motivation but weak connection between intention and moment of action, no specific start time, no cue, and existing habits winning by default. Pre-deciding when, where and how you will start ('if it is 9am, then I open the document') is the best-evidenced fix.