A customer tells you they "used to use" a competitor, "almost signed" with someone else, or "tried the free version" last month. Every one of those phrasings bundles a memory, a self-image and an educated guess. The memory is reconstructed at the moment of the question, not retrieved like a file. The self-image pushes toward the answer that sounds reasonable and diligent. The guess fills the gaps.
Economists have a name for the gap. A stated preference is what someone says they prefer or did, while a revealed preference is what their behavior shows, and where the two diverge the behavior is the truer signal (Koji, stated vs revealed preferences). The idea goes back to Paul Samuelson, who argued we should infer value from choices actually made rather than from claims (Koji).
The size of the gap is not a rounding error. One practitioner summary reports that traditional stated-preference research predicts purchase behavior with roughly 34% accuracy, while behavioral methods reach as high as 89% when properly implemented, and that about 38% of online shoppers act differently from what they previously stated (Koji). Treat those numbers as directional rather than precise, but the direction is consistent: words are cheap, behavior is expensive.
Academic work reaches the same conclusion from a different angle. A review of the reported-versus-revealed preference literature notes that reported answers mislead when respondents do not remember past behavior, do not understand the question, or answer inaccurately, which is exactly the condition of a fast sales call (CEPR VoxEU). The same review found that qualitative reports did carry real information about spending on stimulus payments, just less than observed behavior, which is the useful nuance: reports are not noise, they are weak evidence that needs corroboration (CEPR VoxEU).
Three forces that corrupt a stated alternative
| Force | What happens in the conversation | What the customer says | What often happened |
|---|---|---|---|
| Memory reconstruction | They rebuild the timeline from fragments | "We tried that about six months ago" | A demo, a free trial, or a colleague's mention |
| Social desirability | They want to look diligent and well-informed | "We compared three vendors" | They looked at one pricing page |
| Substitution bias | They name the nearest familiar brand | "It's basically like X" | It solved a different job at a different price |
Substitution bias deserves its own paragraph. Buyers classify your product into the nearest category they already hold in their head, because the category is the frame that determines the comparison set and the budget line the purchase comes out of (10Louder). When a customer says their alternative was "a spreadsheet" or "the incumbent," they may be telling you which budget they think you belong to, not which product they actually evaluated. That is a positioning signal dressed up as a behavioral one.



