Documents such as articles, academic papers, reports, strategy documents, letters can all be converted to variables.
A test of the clarity of the writing is how easy it is to convert the document into a CLD.
We will often discover the missing variables by asking the questions "what else affects X?"
To write well ourselves we can create a CLD and then convert it to writing. You will write some of the clearest documents (with no superfluous fluff!)
For an example of how to identify variables in paragraphs see Hospital Beds.