Combined methods to define metrics reflecting UX quality and project goals.

HEART—UX metrics categories.

• Happiness—user attitudes collected via survey.

• Engagement—user involvement measured via behavioral proxies.

• Adoption—the number of new users of a product/feature.

• Retention—the rate of existing users’ return.

• Task success—behavioral metrics of UX (efficiency, effectiveness, error rate).

Goals-Signals-Metrics—process transforming categories into metrics.

• Goals—Identify the goals clearly.

• Signals—Map goals to lower-level signals sensitive to changes in design.

• Metrics—Refine signals into metrics to track or use in an A/B test.