> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getnovaplan.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Metrics Center

> One registry for every metric on the platform, with formula references between metrics.

Metrics Center is the single source of truth for how every number is defined. Define a metric once and it is available everywhere: KPI cards, table cells, dashboards, reports, and Nova. Because every surface reads the same definition, the same number means the same thing on every screen.

## The Four Metric Kinds

| Kind      | What it is                                         | Example                                         |
| --------- | -------------------------------------------------- | ----------------------------------------------- |
| Primitive | A single aggregation over one field                | Total actual amount                             |
| Ratio     | One metric divided by another                      | Gross margin (gross profit over revenue)        |
| Derived   | A formula that references other metrics            | Operating income from several component metrics |
| Engine    | A platform-computed metric backed by a calculation | ARR movement components                         |

## Formula Syntax

Derived metrics are written as formulas that reference other metrics by code, prefixed with `@`. For example, a gross-margin-percent metric might read:

```
(@gl.gross_profit / @gl.revenue) * 100
```

The editor autocompletes `@code` references as you type, and the formula preview renders each reference as a named pill so the formula reads in plain terms, not raw codes. Referencing a metric that does not exist is flagged, so a formula can never silently point at nothing.

## Why a Registry

* **No drift.** Every surface that shows a metric reads the same definition, so a figure is identical wherever it appears.
* **Single source.** An active metric resolves to exactly one implementation, so a surface never hand-rolls its own version of the math.
* **Traceable.** Click a metric anywhere to see its definition, its formula, and a drill-through.
* **Versioned.** Changing a definition bumps its version, so history stays honest.

## Adding a Metric

<Steps>
  <Step title="Create it">
    In Reporting, open Metrics Center, choose a kind, and define it. For derived metrics, build the formula with the `@code` autocomplete.
  </Step>

  <Step title="Place it">
    Bind it to a KPI card, a table column, or pin it to a dashboard.
  </Step>

  <Step title="Use it">
    The metric is now available to Nova and to anyone building reports.
  </Step>
</Steps>

## Common Questions

<AccordionGroup>
  <Accordion title="What is the difference between a ratio and a derived metric?">
    A ratio is exactly one metric over another. A derived metric is a full formula that can combine several metrics with operators, so it handles anything beyond a single division.
  </Accordion>

  <Accordion title="Why does my metric show a label but no value?">
    A metric needs a source: a bound calculation for primitive and engine kinds, or a compiled formula for derived and ratio kinds. Without one it can render its label and definition but cannot produce a number.
  </Accordion>

  <Accordion title="Does editing a metric change history?">
    The definition is versioned. Editing it bumps the version so prior reports remain explainable, and the change is traceable.
  </Accordion>

  <Accordion title="Can two pages show different values for the same metric?">
    They should not. If they do, one surface is computing its own number instead of reading the metric's single source. The registry exists precisely to prevent that.
  </Accordion>
</AccordionGroup>

## If the Numbers Look Off

* If a derived metric reads blank, confirm every `@code` it references exists and resolves; one missing reference can empty the whole formula.
* If a metric disagrees across two surfaces, treat it as a binding problem (one surface not reading the registry), not a data problem.

<Tip>
  Metrics defined here flow straight into [Report Builder](/reporting/report-builder), dashboards, and Nova, so define once and reuse everywhere.
</Tip>