Use Cases

What it is

A single metric capturing core value delivery to users, decomposed into input metrics through a metrics tree. Aligns the entire organisation around long-term goals.

When to use

When a team has no shared definition of success. When sprint priorities are dictated without data. When engineering and leadership have different ideas of what good looks like.

When NOT to use

When two fundamentally different user segments get fundamentally different value, you need two complementary NSMs. Forcing one NSM creates false trade-offs.

What it is

A structured 5-step process: check data integrity, segment by user type, segment by channel, compare to external causes, trace to specific user action.

When to use

Any time a key metric moves significantly, up or down. Unexplained increases are as suspicious as unexplained drops. Both require the same diagnostic process before response.

When NOT to use

When the cause is already known (a planned feature shipped). Document the expected impact instead and compare actual vs expected after two weeks.

What it is

For every primary metric you optimise, a counter-metric detects if you are creating harm while improving the target. Counter-metrics catch the cases where you win the metric but lose the product.

When to use

Always. No metric should exist in production without a counter-metric. This is especially critical for engagement, notification, and recommendation systems.

When NOT to use

Counter-metrics are always relevant. If you cannot identify one, the primary metric is probably not specific enough.

What it is

Google’s framework for measuring user experience quality across five dimensions: Happiness, Engagement, Adoption, Retention, and Task Success.

When to use

When evaluating a specific feature or redesign. When you need qualitative and quantitative signals together. When a stakeholder says “How do we know if the new onboarding is better?”

When NOT to use

As a replacement for AARRR at the funnel level. HEART is a quality framework for features, not a growth framework for products. Do not use it to set company OKRs.