metrics

name	metrics
description	Define success metrics and KPIs for a feature or product. Identifies leading and lagging indicators with instrumentation guidance. Use when user says "define metrics", "KPIs", "how do we measure success", "success criteria", "what should we track", "instrumentation plan", or needs to quantify outcomes.
user-invokable	true
args	[{"name":"target","description":"The feature or product to define metrics for (optional)","required":false}]
metadata	{"author":"builder-skills","version":"1.0.0"}

Define what success looks like in numbers. Work through each step — don't jump to a list of metrics without grounding them in the goal first.

Step 1: Identify the Goal

Before picking metrics, answer:

• What job does this feature serve? What progress is the user trying to make? (Reference the jtbd skill if available.)
• What outcome matters to the business? Revenue, retention, efficiency, expansion — pick one.
• What behavior change are you expecting? Users should do more of X, less of Y, start doing Z.

If you can't state the goal in one sentence, the metrics will be unfocused. Push for clarity.

Step 2: Define a Primary Metric

Pick the ONE number that best represents success. This is the metric the team checks every morning.

How to choose — the 3 A's:

Test	Question	Bad example	Good example
Actionable	Can the team change this number with their work?	Total registered users (too broad)	Weekly active users of this feature
Accessible	Can everyone on the team understand and check it?	Custom composite score	% of users who complete core action
Auditable	Can you verify the data is correct?	Self-reported satisfaction	Event-tracked completion rate

Common primary metrics by goal:

Goal	Primary metric
Adoption	% of eligible users who use the feature in first 7 days
Engagement	Weekly active usage (sessions, actions, or time)
Retention	% still using after 30 days
Efficiency	Time to complete task (before vs. after)
Revenue	Conversion rate or revenue per user
Quality	Error rate or task success rate

State it precisely: "% of users who create at least one invoice within 7 days of first seeing the feature" — not "adoption."

Step 3: Define Supporting Metrics

Leading indicators

Predict future success. Move before the primary metric does. Use these to course-correct early.

Example	What it predicts
Activation rate (completed setup)	Future retention
Feature discovery rate (saw the entry point)	Future adoption
Time to first value	Future engagement
Onboarding completion	Future active usage

Lagging indicators

Confirm past success. Move slowly. Use these to validate that early signals were real.

Example	What it confirms
30/60/90-day retention	Sustained value
Net revenue retention	Business impact
NPS / CSAT change	User sentiment shift
Support ticket volume (down)	Reduced friction

Guardrail metrics

Things that should NOT get worse when the feature launches. Set these before shipping.

Guardrail	Threshold
Page load time	Must stay under current p95
Error rate	Must not increase >0.1%
Existing feature usage	Must not drop (cannibalization check)
Support ticket volume (up)	Spike is okay for 1 week, not 4
Unsubscribe rate	Must not increase after announcement emails

If a guardrail breaks, investigate before celebrating the primary metric.

Step 4: Anti-Metrics — What NOT to Track

Vanity metrics feel good but don't inform decisions. Ignore these:

Vanity metric	Why it's misleading	Track this instead
Total signups (all time)	Only goes up, tells you nothing	Weekly new active users
Page views	Traffic without context	Conversion rate from page
Total features shipped	Output, not outcome	Adoption rate per feature
App downloads	Acquisition without activation	Day-7 retention
Time on page (alone)	Could mean engaged or confused	Task completion rate

Rule of thumb: If a metric can only go up and never triggers action, it's vanity.

Step 5: Instrumentation Plan

Metrics are useless without reliable tracking. For each metric, define:

Event name	Trigger	Properties	Where tracked
feature_viewed	User sees the feature entry point	user_id, source, timestamp	Analytics (e.g., Amplitude, Mixpanel)
feature_activated	User completes core action for first time	user_id, time_to_activate, timestamp	Analytics
feature_used	User completes core action (any time)	user_id, session_id, timestamp	Analytics
feature_error	Something fails	user_id, error_type, timestamp	Error tracking (e.g., Sentry)

Instrumentation checklist:

• Events fire in both frontend and backend where appropriate
• User ID is attached to all events (for cohort analysis)
• Timestamps are consistent (UTC)
• Properties include enough context to segment (source, plan, cohort)
• Events are tested in staging before launch
• Dashboard or report is built before launch day
• Team knows where to check metrics and how often

Metrics Template

Use this table as the deliverable:

| Metric | Type | Target | How to Measure |
|--------|------|--------|----------------|
| [Primary metric] | Primary | [specific number] | [event/query] |
| [Leading indicator 1] | Leading | [specific number] | [event/query] |
| [Leading indicator 2] | Leading | [specific number] | [event/query] |
| [Lagging indicator] | Lagging | [specific number] | [event/query] |
| [Guardrail 1] | Guardrail | [must not exceed X] | [event/query] |
| [Guardrail 2] | Guardrail | [must not exceed X] | [event/query] |

If You Can Only Track 3 Things

When instrumentation budget is tight, track exactly these:

1. Adoption — did users find and try it? (feature_activated / eligible users)
2. Completion — did they succeed at the core task? (task_completed / task_started)
3. Return — did they come back? (feature_used where usage_count > 1 within 14 days)

These three form a funnel: discovered it, got value, came back. Everything else is refinement.

Output

Deliver the metrics plan as a document with:

1. Goal — one sentence
2. Primary metric — name, definition, target
3. Supporting metrics — leading, lagging, guardrails in table format
4. Instrumentation plan — events, properties, where tracked
5. Anti-metrics — what you're deliberately not tracking and why