---
title: "FactsInput"
description: "a unit or a population, as of two dates"
section: concepts
address: /concepts/factsinput
contract: 0476e35e6e275db5
---

# FactsInput

a unit or a population, as of two dates

[figure: FactsInput is a value at none scope. The drawing shows its fields and the objects that they point at.]

| property | value |
|---|---|
| kind | value |
| scope | none |
| key | none |
| store | none |
| family | harness |



## Fields


| field | type | required | note |
|---|---|---|---|
| `unit` | [UnitRef](/concepts/unitref) | no |  |
| `population` | [Predicate](/concepts/predicate) | no |  |
| `attributes` | `[text]` | no |  |



## Routes that use it
- [`/v1/ask/facts`](/reference/ask/facts) takes it as input