# Information casualty

> An information casualty is an event in which relevant information fails to reach an observer in time to inform perception, action or participation.

**Real.** This entry is about something real, written from outside the CharliVerse.

An **information casualty** is an event in which relevant information fails to reach an observer in time to inform perception, action or participation. It is the founding concept of the [Tyrer Framework](https://charli.info/charlipedia/tyrer-framework/) and gives the [Zero Information Casualty](https://charli.info/charlipedia/zero-information-casualty/) standard its name.

The term is deliberate. When a blind pedestrian walks into an obstacle because nothing signalled it, that is not a usability issue; it is a failure in the information layer of the environment. When an interface renders a critical control as an unlabelled picture, the person who can't perceive it hasn't been inconvenienced; they have been cut off from what they need to act. Information casualties are not edge cases. They are the predictable output of [Tyrer's Law](https://charli.info/charlipedia/tyrers-law/).

## Every word works

The ZIC standard reads the definition closely. *Reach* means the failure can happen anywhere between publisher and reader: in the encoding, at the door, on the wire, or inside the machine that read it. *In time* means that arrival at prohibitive cost or intolerable delay is a failure of arrival: "A reader forced to labour for information that another reader receives at a glance has not been served equally; she has been served late."

## The four classes

ZIC names four places the failure can happen, each with a question:

1. [Rendering Casualty](https://charli.info/charlipedia/rendering-casualty/): can they read it?
2. [Admission Casualty](https://charli.info/charlipedia/admission-casualty/): is the person's reader allowed in?
3. [Delivery Casualty](https://charli.info/charlipedia/delivery-casualty/): did it actually arrive?
4. [Reconstruction Casualty](https://charli.info/charlipedia/reconstruction-casualty/): did it survive being read?

The definition is one; the classes are where it breaks.

## Behind the scenes

A real idea, defined in [The Tyrer Framework](https://carrados.com/papers/tyrer-framework/) (Part One) by Charli-Jo Tyrer, and divided into four classes in [Zero Information Casualty v1.7](https://carrados.com/papers/zic-design-standard/) (§1.8). This entry summarises them; the documents are the authority.