Scale compatibility
Also known as: Scale-compatibility effect, Response scale compatibility
An attribute gets over-weighted when it is already in the units of the answer.
What it means
Scale compatibility is the finding that an attribute carries more weight in a judgment the more closely it matches the scale on which the response must be given. The mechanism is mapping and fluency: information already expressed in the units of the required output can be used directly, with no translation, so it is easier to weigh and ends up dominating, while attributes that need converting into those units get discounted. It is the engine behind classic preference reversals, since pricing a gamble in dollars makes the dollar payoff decisive while choosing weights the chance of winning. It surfaces wherever value is elicited numerically: willingness-to-pay surveys, salary-matching tasks, rating scales, scoring rubrics. The limit is that it does not identify which response is correct; both are constructed, so neither is the true preference. It matters because the instrument manufactures part of the answer it claims to record.
Examples
Asked which insurance plan they prefer, people pick the one with better coverage; asked what premium would make the plans equivalent, they weight the dollar deductible far more and reverse their ranking.
A hiring panel scoring candidates 0-100 leans on the attribute already numeric, the test score, while judged qualities like fit recede; asked simply to pick someone, fit drives the decision.
Contingent-valuation surveys ask what people would pay to protect a wetland; because the answer is in dollars, dollar-like features dominate and the ecological attributes that motivated the survey get quietly discounted.
First described in Tversky, Sattath & Slovic (1988); Slovic, Griffin & Tversky (1990).