Dave Child, a web developer in the UK, is a a creator and an advocate of cheat sheets — his term for quick reference guides. He’s also the founder of Cheatography, a site which helps people create and share on-the-job guides like the PHP Cheat Sheet (link is to a PDF version).
Who uses this job aid?
PHP is “a general-purpose server-side scripting language” used to produce dynamic web pages. The person using this cheat sheet is most likely competent in working with PHP. Not that a neophyte can’t benefit at all, but such a person probably lacks a good deal of helpful context.
What’s the task it supports?
This is an example of what I call a reference job aid. It doesn’t guide a specific task, the way the fire-shelter inspection guide does. Instead, it organizes certain information in a way that’s helpful in a number of different but related situations: often a quick look at the job aid is sufficient. You aren’t sure of the code if you want a long month name (“September”) versus a short one (Sep). Or you want to check the syntax of a regular expression function. So you go to the cheat sheet.
(Tangent: In my experience, organizations that frown on terms like “cheat sheet” aren’t usually strongholds of effective on-the-job support. All the more so if the people doing actual work refer to their quick reference materials as cheat sheets–and wouldn’t dream of letting someone take them away.)
One challenge in creating a reference job aid is deciding what information to include (and what to deliberately leave out) and how to organize it. The PHP cheat sheet uses boxes and subtitles as an organizing principle. Here’s Dave Child’s own description of how he came up with the first version:
I wrote the first one waaaaay back in 2005 because I was visiting the PHP manual so often for the same information. I’d started printing pages from the manual and jotting notes down all over my desk, and eventually decided this was just silly and organised all the notes into one page. The layout wasn’t really planned at that point.
This is the way a lot of job aids begin, especially ones for reference: people note the things that are helpful to them, but that they don’t seem to remember. If you’re looking to support the performance of others, spend some time trying to find out what’s on homebrew job aids. They may not have the best design; they may even include errors or misconceptions. But they invariably highlight information that the person (a) sees as important and (b) has trouble keeping in memory.