Expectancy-Disconfirmation (Oliver)期望失验（Oliver）

Satisfaction = f(Perceived Performance − Expectation)

Satisfaction is not the absolute quality of what you got; it is the signed gap between what you experienced and what you expected. Positive disconfirmation (performance > expectation) → satisfaction; negative → dissatisfaction; met expectation → neutral.

Difference form = the gap is felt, not the level. The same performance can delight or disappoint depending only on the expectation it was measured against. This is the academic root of 过瘾 ("satisfaction = experienced value − expected value, when positive") — and it explains the danger of your own hype: over-promising raises the expectation term and manufactures negative disconfirmation from a good product.

Transfer. Two levers, and the cheap one is usually the expectation. Under-promise in the setup so the payoff clears the bar (the reason a modest hook that over-delivers beats a grand hook that merely delivers). For content specifically: a title that oversells guarantees a dissatisfied reader even from good writing. Set the expectation you can beat.

Kin: illustrative-formulas · servqual-gap (the service-quality version) · two-pleasures-arousal-and-closure · delivery-craft P14 (truthful cues, don't inflate the expectation).

Source: Richard L. Oliver, "A Cognitive Model of the Antecedents and Consequences of Satisfaction Decisions," Journal of Marketing Research 17(4), 1980 — the expectancy-disconfirmation paradigm