# ParetoStrip (/docs/charts/pareto-strip)

ParetoStrip answers "what should we fix first?". It sorts the categories descending and overlays a **cumulative-share
line on a fixed 0–100% scale** that spans the full height and is never rescaled to steepen the curve. The bars up to the
threshold crossing are accent — the **vital few** — and the rest are muted, because the chart's one job is to say where
to stop reading. 80% is a working reference, not a law, and `Other` never re-enters the ranking.

```tsx
<ParetoStrip
  data={[
    { label: "Timeouts", value: 38 },
    { label: "OOM", value: 24 },
    { label: "Deploy", value: 15 },
    { label: "Config", value: 9 },
    { label: "Network", value: 7 },
    { label: "Auth", value: 4 },
    { label: "Disk", value: 3 },
    { label: "DNS", value: 3 },
    { label: "Other bug", value: 2 },
  ]}
  unit="causes"
  metric="incidents"
  title="Incident causes"
  width={260}
  height={28}
/>
```

## Install

```tsx
import { ParetoStrip } from "@microcharts/react/pareto-strip";

<ParetoStrip data={causes} unit="causes" metric="incidents" title="Incident causes" />
```

Setup (package + stylesheet): [Quickstart](/docs/quickstart#set-up-with-an-ai-agent) or paste [`/agent-setup.md`](/agent-setup.md) into your agent.


## When to use it

- **Good for** — a "fix these three" read in a KPI card, incident causes or support tags in a tab header, any long-tail
  composition where a few dominate.
- **Avoid for** — a plain ranking (MiniBar) or parts of a single whole (SegmentedBar).


## Variants

```tsx
const causes = [
  { label: "Timeouts", value: 38 },
  { label: "OOM", value: 24 },
  { label: "Deploy", value: 15 },
  { label: "Config", value: 9 },
  { label: "Network", value: 7 },
  { label: "Auth", value: 4 },
];

<ParetoStrip data={causes} maxItems={3} />
<ParetoStrip data={causes} threshold={false} />
```

## Edge cases

```tsx
// the first cause alone crosses 80% — one accent bar, the rest muted:
// "Top 1 of 3 causes account for 90% of incidents."
<ParetoStrip
  data={[
    { label: "Timeouts", value: 90 },
    { label: "OOM", value: 6 },
    { label: "Deploy", value: 4 },
  ]}
  unit="causes"
  metric="incidents"
/>
```

```tsx
// all-zero values render no bars and announce "No recorded incidents."
<ParetoStrip data={[{ label: "a", value: 0 }]} metric="incidents" />
```


## Why this default

The accent stops at the crossing, because the chart's one job is to say where to stop reading. The cumulative scale is
fixed 0–100% and shares the full plot height — never rescaled to make the curve look steeper — and 80% is a
**reference** default you can move or turn off, never a claimed law. `Other` is rendered honestly at its true size but
always last and never counted among the vital few; if it towers over the top cause, that usually means `maxItems` is set
too aggressively.

## Accessibility

The accessible name states the vital-few count and its cumulative — **"Top 1 of 3 causes account for 90% of
incidents."** — or, when there is no threshold (or no ranked cause reaches it), the top cause and its share, as in the
rolled-up demo above: **"Timeouts leads at 39%."** The interactive entry steps the bars and announces each bar's share
and running cumulative; **T** jumps to the crossing bar.

The interactive entry follows the shared [interaction contract](/docs/accessibility#one-interaction-contract):
arrow keys rove between units on both axes, `Home` and `End` jump to the ends, and a click, tap, `Enter` or
`Space` selects a unit — pinning its readout so it survives blur, until you select it again or press `Escape`.
On touch, a tap pins and a drag scrubs.

## Props

| Prop | Type | Description |
| --- | --- | --- |
| `data` (required) | `{ label; value }[]` | Categories with magnitudes — the component sorts descending. |
| `threshold` | `number \| false` | Cumulative reference line % (default 80 — a working reference, not a law). |
| `maxItems` | `number` | Categories beyond maxItems roll up into Other (default 8, always last). |
| `unit` | `string` | Category noun for the summary (default 'causes'). |
| `metric` | `string` | Total-metric noun for the summary (default 'the total'). |
| `label` | `"count" \| "none"` | 'K of N → cum%' in a right gutter. |
| `animate` | `boolean` | (interactive) Opt-in entrance motion when the chart mounts client-side — add `import "@microcharts/react/motion"` once. Inert on the server, on hydrated server HTML, and under `prefers-reduced-motion`. |

Plus the shared grammar — `data`, `domain`, `color`, `title`, `summary`, `format` — and the layout props (`width`, `height`, `className`, `style`) that every chart accepts. Interactive entries also share `animate` and `live`, and — wherever a chart has more than one navigable unit — `onActive`, `onSelect`, `selectedIndex` and `defaultSelectedIndex`; and — wherever the chart shows a hover value — `readout`. See [the shared grammar](/docs/quickstart#the-shared-grammar).