Lemma
No. 100

UX Design

Usability

Usability is how easily and effectively people can use a product to achieve their goals.

Why it matters

A product can look stunning and still be hard to use. Usability is what determines whether people actually succeed and come back.

In depth

Usability is commonly measured across dimensions like learnability, efficiency, memorability, error rate, and satisfaction. It is best assessed by watching real people attempt real tasks. High usability often goes unnoticed — it simply feels like the product works.

Real-world example

A checkout that lets you pay in two taps without creating an account has higher usability than one demanding a long form before purchase.

Visual

Principle

Usability

How easily people actually succeed at what they came to do.

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