---
title: "KeyFitness"
description: "how often a key is present, and how often two different things share a value"
section: concepts
address: /concepts/keyfitness
contract: 0476e35e6e275db5
---

# KeyFitness

how often a key is present, and how often two different things share a value

[figure: KeyFitness is a fact at platform scope. The drawing shows its fields and the objects that they point at.]

| property | value |
|---|---|
| kind | fact |
| scope | platform |
| key | the kind, the namespace and the window |
| store | postgres |
| family | identity |



## Fields


| field | type | required | note |
|---|---|---|---|
| `kind` | [KindOfEntity](/concepts/kindofentity) | yes |  |
| `namespace` | `text` | yes |  |
| `window` | [Window](/concepts/window) | yes |  |
| `present_share` | `share` | yes |  |
| `shared_share` | `share` | yes |  |



## Routes that use it
No route takes or returns KeyFitness directly. The record holds it, and the objects that point at it reach it.