AMCE and ATE Explained for Conjoint Surveys
Plain-language definitions of AMCE, ATE, reference levels, uncertainty, and long-format conjoint data.
Quick Answer
In a conjoint survey, an AMCE or ATE describes how showing a profile level changes the probability that a profile is chosen, usually relative to a reference level and estimated from profile-level long data.
What the estimate means
A conjoint estimate is usually a change in choice probability. If a level has an estimate of 0.08, profiles with that level were about eight percentage points more likely to be selected than comparable profiles at the reference level, within the model and design.
Why long-format data matters
Conjoint tasks show multiple profiles to the same respondent. The analysis file should include every shown profile, not only the selected profile, and should preserve respondent IDs for clustered uncertainty estimates.
How to communicate uncertainty
Plots and tables should label reference levels, show confidence intervals, and avoid implying that aggregate estimates reveal every individual respondent's preference.
FAQ
Is an AMCE a percentage-point effect?
When the outcome is a binary choice and the model is a linear probability model, the estimate can often be read as a change in choice probability.
Why cluster standard errors by respondent?
The same respondent answers multiple tasks, so profile rows from that respondent are not independent observations.