People are unreliable narrators of their own decision-making.
Ask someone what would change their mind (what evidence they'd need, what factors matter most, what would make them choose differently) and they'll tell you something that sounds reasonable. It might align with their self-image. It might be what they think you want to hear. It might be what they genuinely believe about themselves.
But it's probably not what will actually move them.
This is the gap between stated preferences (what people say) and revealed preferences (what people do). And it shows up everywhere.
Why the gap exists
We're poor predictors of our own behavior, especially in hypothetical scenarios. When you ask what someone would do, you're asking them to simulate a future self making a decision under conditions they're not currently experiencing. Their answer can reflect an aspiration that differs from the trade-offs they make in practice.
Social desirability bias (the tendency to report what looks good rather than what's true) and post-hoc rationalization can widen the gap. Past choices generally deserve more weight than stated intentions when anticipating behavior; sometimes they are the best evidence available.
Where it shows up
Consumer research: Survey respondents say they'll buy the sustainable option. Sales data shows they chose the cheaper one. Their purchases are stronger evidence of what they are likely to buy at those prices than their survey answers.
Resource allocation: Leadership says people are the organization's greatest asset. When budgets tighten, training and development are first to get cut. The cuts show which commitment leadership protected when money was tight.
Stakeholder relations: A funder says they value innovation and risk-taking. Their decade of grants went to proven, low-risk initiatives. That record is stronger evidence for anticipating their next grant than their stated appetite for risk. It does not establish why they chose those projects.
The alternative: decision archaeology
Instead of asking what would move someone, examine what has actually moved them.
What did they fund last time? What did they buy when given the choice? What got prioritized when resources were tight?
Those choices show which priorities prevailed under the conditions people actually faced. Repeated patterns are strong evidence for anticipating future decisions; the available alternatives and constraints help explain what those patterns mean.
This is decision archaeology: excavating actual patterns rather than accepting stated rationales.
Origins
Revealed preference theory comes from economist Paul Samuelson (1938), who argued that preferences are best understood through observed choices rather than stated intentions. If someone consistently chooses A over B when both are available, that reveals their preference more reliably than asking which they prefer.