Happiness, Engagement, Adoption, Retention, Task success — Google's five-dimensional model for measuring user experience quality at scale. The categories, the goal-signal-metric structure, and why it complements business metrics.
Attribution. The HEART framework was developed by Kerry Rodden, Hilary Hutchinson, and Xin Fu at Google around 2010 and published in a 2010 CHI conference paper. It became the standard UX measurement approach across Google products and has been widely adopted across the tech industry. This article reviews the framework.
The five categories
HEART organizes UX measurement into five categories. Each category captures a different aspect of user experience.
Happiness. Attitudinal — how do users feel about the experience? Captured via satisfaction surveys, NPS, perceived ease of use.
Engagement. Behavioral — how often, how deeply, how long do users interact? Sessions per user, depth per session, intensity of use during sessions.
Adoption. New user pickup — how many new users start using a feature or product?
Retention. Returning users — how many users continue using over time?
Task success. How efficiently and effectively do users complete the things they came to do?
The Goals-Signals-Metrics process
HEART pairs with a process called Goals-Signals-Metrics for picking the actual measurements:
Goals. For each HEART category, what does success look like for this product? "Users feel confident enough to recommend us" might be the Happiness goal.
Signals. What behavior or attitude would tell us we're moving toward the goal? "Higher NPS scores" might be a signal for the above goal.
Metrics. The specific quantitative measurement. "NPS score on the post-purchase survey, measured monthly, segmented by purchase value" is a metric.
The three-step process forces teams to articulate why each metric matters — preventing the common failure of measuring whatever is easy to measure.
Why HEART matters for marketers
Most marketing measurement focuses on acquisition (CAC, conversion rate, CTR) and revenue (LTV, ARR, MER). HEART captures the experience quality that drives all the downstream business metrics. If Happiness, Engagement, and Task success are weak, marketing has to work harder forever — every customer churns sooner, every reference is harder to earn, and acquisition efficiency erodes.
Companies that monitor HEART metrics alongside business metrics catch experience degradation before it shows up in revenue. Companies that only monitor business metrics learn about experience problems through churn, six months too late.
HEART is not exhaustive. Not every product needs all five categories. A one-off purchase product cares about Adoption and Task success, less about Retention. A daily-use SaaS product cares about Engagement and Retention more than one-time Task success. Pick the categories that map to your product's actual user behavior.
Common applications
Onboarding redesign: Adoption metrics tell you how many new users complete the first key action. Happiness tells you how the onboarding feels. Task success tells you whether they're achieving what they came for. All three matter for evaluating a new onboarding flow.
Feature launch: Engagement metrics show whether the feature is being used. Adoption shows how broadly. Retention shows whether use sustains over time.
Site / app redesign: Pair Task success (can users still complete key flows?) with Happiness (do they like the new experience?) to evaluate launch impact.
Related on RGM
North Star Metric — pairs with HEART (NSM is the one number; HEART is the diagnostic layer).