It seems that, by now, the importance of considering the audience is somewhat cliché. Of course this is the theme of these chapters which plays into how one plans these sorts of documents. The readings discuss the vital role of researching even things that seem, to the advanced user, benign or irrelevant. Figure 20.5 may be excessive for some applications, but it does a good job at expressing many of the points for consideration when formulating a set of instructions.
The text also mentions being specific. This is a crucial aspect of instructions, as pointed out in the instructor blog example with the car. However, it is somewhat of a balance act, on one hand you must be as descriptive and precise as possible, but on the other hand you don't want to get too hung up on the technical details to the point where your primary reader simply gets lost in the vocabulary.
One of the readings pointed out the necessity for field testing the instructions to make sure that they are adequate. The people who wrote/built this shelving unit I put together last summer clearly skipped this step. The drawings indicated locations for screws, but these did not exist at all on the actual pieces. It was, of course, frustrating at first, but then I just tossed the instruction manual aside and ended up putting it together based on how I thought the builders intended.
As far as the 'idiot' approach goes...I can think of a few people that this would cater too...but mostly I would think that it could add unnecessary length to the document. It may, in an effort to reduce complexity, actually increase it by specifying so many things. I think this is a simple matter of understanding your primary readers and estimating their knowledge.
Audience Audience Audience...
I agree that the readings do seem to stress a user-centered, audience-aware approach time and time again, but I really think its necessary considering the shear importance and relevance. I don't mind being reminded and wouldn't consider myself an advanced writer by any means.
I think your third reference, considering the field testing of instructions, is an interesting illustration of an instance where the user (you) gave up confidence in the instructions because of their lack of accuracy. I have also thrown seemingly irrelevant directions aside in the past due to similar inaccuracies, and I think this really point out the importance of making your directions as accurate and field-tested as possible, without being overly-complicated.
Description R7
I agree with you when you say it is a balancing act of how much description to put into your instructions. You cannot lose your primary reader, however I think that most instruction writers would be smart to consider that at least some part of their instructions will be skipped over. Keeping this in mind will mean that you will structure your document to be easier to read through and get to the parts you need. No reader is the same so some of them will be skipping parts that are crucial to others. That’s why I think flexibility is a main key to writing these types of documents.
Shane
Instruction Sets
You mention how instructions need to perform a balancing act between several factors including audience expertise and document length. I've always found the best instructions just include multiple sets of instructions. One set which assumes an expert audience, such as a "quick start" guide, and then a detailed step-by-step instruction set for beginner or intermediate level audiences.
I too have run into problems where clearly the instructions weren't tested in the field, or don't apply specifically to your model. This can create frustration for the user of the instructions, and can easily cause the user to put down the manual and figure it out for themselves as in your case.
Graphics
I certainly understand where you're coming from. I couldn't believe it when I tried to put together an entertainment unit that the instructions consisted of four pictures when the box had five different screws and multiple brackets. At least the eight steps to put it together were printed in five languages (very helpful use of space). I find it so frustrating that manufacturers never consider their audience when creating instructions.
The readings from the employment project will really help me to complete these instructions. By using the 5 W's like is says to in Chapter 20, I will put myself in the shoes of those who will actually be reading the instructions I'm writing.
Mike Sheridan
Don't treat the reader like an idiot
You bring up a good point. When writing instructions, you should make them simple, but not too simple. Don't treat the reader like a complete idiot and waste their time. For example, it's enough to tell the reader to press the green button -- you don't have to explain how to press a button.