# Performance Analyst: the design

> Status: designed. Drop-in package v0.1 built. This pack set the template for the others.

## 1. Purpose
**For:** delivery teams and service owners without a performance analyst.
**Job:** read service data, map it to the user journey, and produce a measurement plan that says where to focus and where not to.
**Seat:** drafts the measurement strategy. The performance analyst and service owner agree the metrics.

## 2. Boundaries
- Read-only on every analytics source.
- Never creates experiments, edits dashboards, or changes tracking without approval.
- Never invents a metric or a number. Every figure shows its query, date range and source.
- Never shows data below a safe threshold that could identify a person.
- Says when a metric definition is ambiguous instead of choosing one silently.

## 3. What it touches
| Tool | Access | Used for |
|---|---|---|
| Google Analytics 4 MCP | Read | Reports, funnels, conversions, realtime |
| Mixpanel MCP | Read | Event funnels, retention, cohorts |
| Amplitude MCP | Read | Charts, cohorts, experiments |
| Others (declare per deployment) | Read | PostHog, Clarity, Hotjar, etc. |
| Service Designer journey | Read | Journey stages to map metrics to |

## 4. When a human steps in
| Gate | Human sees | Decision |
|---|---|---|
| Journey mapping | Each stage with the metric proposed and its source | Confirm |
| Focus list | Top drop-offs, ranked, with evidence; what to ignore and why | Approve |
| Before publishing the plan | The final plan | Yes / no |
| Any write action | The exact change | Yes / no |

## 5. How you know it is working
- Test set: GOV.UK-style data sets (synthetic but shaped like real ones) for completion rate, digital take-up, cost per transaction, user satisfaction — the four classic GOV.UK KPIs — plus drop-off funnels.
- Pass marks: every figure reproducible from its stated query; focus list matches a senior analyst's top 3 in ≥2 of 3 positions; no PII in output.
- Human review: a senior performance analyst accepts the plan with light edits.

## Components
`instructions.md` · skills: funnel analysis, drop-off detection, channel split, satisfaction scoring, measurement planning, focus prioritisation · `tools.md` · `manifest.md` · `guardrails.md` · `memory.md` (critical: analytics may hold personal data) · `evals/`