You decided to read this article on a whim, and I'm glad you did. Not all decisions require a decision matrix. I'm an author, so I use decision matrices to methodically decide what's going to happen in a story. After completing a decision matrix, I'm satisfied with my choice and I can concentrate on writing about the option I selected.
In preparing to describe how I use decision matrices to make decisions, I noticed that Boing Boing's primary reference to decision matrices is highlighting another website's flowchart. It's a great flowchart. It's just not a decision matrix.
Decision matrices start with a matrix, in this context defined as a rectangular array of elements. A blank spreadsheet is fine. If you abhor spreadsheets, use any other medium you can make rows and columns with, but keep in mind that the decision at the end involves some elementary math. This is an example of customizations I'll suggest while I'm explaining decision matrices, to make the technique work well for you.
Now that you have an empty matrix, define the problem you want to solve. If you're into the 5 why's technique, or if you've never tried it before, this is a good place to use it. If you'd rather meditate or walk or shower to let your subconscious define the problem, that may work better for you. A decision matrix is a tool, so make sure you're applying it to the question which will get you the results you want.
A simple question which a decision matrix can answer is "What should I write about?" List every possible option in the first column. Read the rest