# Quantity

> How much there is, measured by a device instead of estimated by a person.

- **Page** - https://iotready.com/academy/traceability-foundations/quantity
- **Course** - [Traceability Foundations](https://iotready.com/academy/traceability-foundations.md)
- **Lesson** - 2 of 3
- **Level** - Foundation
- **Time** - 15 min

## What counts as quantity

Weight, temperature, humidity and dimensions are all quantity, and so is a
count. A count is the one people are most tempted to do by hand.

## Measuring in one pass

- **1** Pass over the scale
- **4** Values captured
- **0** Keystrokes

## Why estimation fails

An estimate is a number with no witness. It survives into the ERP and becomes a
fact nobody can trace back to anything.