Not all features earn satisfaction the same way. Some are only noticed when missing, some pay off in proportion to how good they are, and a few delight precisely because nobody expected them. The Kano model exists because "important" is not one thing, and treating it as one thing produces forgettable products.
In this glossary topic:
What is the Kano model?
The Kano model is a prioritization framework that classifies features by the relationship between how well they are executed and how satisfied users are, rather than by a single importance score. Developed by Noriaki Kano in the 1980s for quality management, it moved into product work because it answers a question flat rankings cannot: what kind of satisfaction is this feature capable of producing?
How does the Kano model categorize features?
Three categories carry the weight. Basic expectations are the features whose absence infuriates and whose excellence goes unnoticed; login works or it does not, and nobody praises a login. Performance features scale satisfaction with quality, so faster search and longer battery life keep paying as they improve. Delighters produce outsized satisfaction because they were never expected, and their signature property is decay: yesterday's delighter becomes tomorrow's basic expectation, which is why the categories describe a moment, not a permanent truth. Classification comes from asking users paired questions, how they would feel with the feature and without it, rather than from the team's own intuition.
Why does the Kano model matter?
It prevents two expensive mistakes that flat prioritization invites. The first is over-polishing basics, spending quarters perfecting a feature whose satisfaction ceiling was reached at "works reliably". The second is shipping a product that is complete but joyless, every basic covered, nothing that anyone remembers. Kano makes the portfolio visible: enough basics to avoid anger, enough performance to compete, and a deliberate delighter or two, chosen knowing the delight will not last.
