A good example comes from the forensics world: chain of custody versus chain of evidence. Often we see these two terms used interchangeably. They actually have very different meanings. Chain of evidence is the chain of events that led to the incident. The chain can be temporal (this happened, then this happened) or causal (this happened because that happened).
Chain of custody refers to the way evidence is handled. You need to be able, with certainty, to account for every access to the evidence from the time it is collected until the time it is used.
In reviewing documents such as policies and standards, or response plans where there are detailed instructions for actions to be taken in an emergency, it is critical that readers are very clear on what needs to be done. Terminology plays a big role, so you should define your terms in technical documents as well.
I cannot recall the last time I saw an important document or incident report where a glossary was included. In teaching mid-career adults taking a master's degree in information assurance,
I have found that the ability to communicate clearly in writing is one that should never be taken for granted. This is another reason for defining terms in critical documents.
It is bad enough that information flow in a document is confusing. If terminology is poorly defined, the document becomes unusable. So what is the answer?
First, those of us who write critical documents need to be able to write. If you have the luxury of a technical writer in your group, use them. It does not matter, it seems, whether the writer is an expert on the subject matter. Subject matter experts can communicate the important information to the writer. The writer makes it useful. Good technical writers are skilled in performing this type of magic. If you don't have that luxury, my suggestion is that you get the best writer in your group, or another group, to review all document before releasing them.
The bottom line is to say what you mean to say so that others, especially in an emergency, can take advantage of it. And be sure that other see things the same you do.
Peter Stephenson, Norwich University