January 05, 2011

A foundation for writing guidelines

I've been several times in a situation where I had to write guidelines for one of our clients . Guidelines, instructions, procedures, protocols, ... some seem more strict than others, but they all suffer from the same problem: how to clearly indicate the do's and don'ts.

A few years ago, I got inspired by what is known as an RFC (Request for Comments) in the internet world. Very roughly speaking, RFCs describes how machines must communicate over the internet. One RFC in particular (RFC 2119), written by Scott Bradner from Harvard University, describes some key words to signify the requirements in a (RFC) document.

Although the RFC clearly states that "they must not be used to impose a particular method they must not be used to try to impose a particular method on implementors where the method is not required for interoperability" (roughly speaking for the internet again), I found them very useful for guidelines in general.

The key words are as follow (excerpt from the originial document):
  1. MUST - This word, or the terms "REQUIRED" or "SHALL", mean that the definition is an absolute requirement of the specification.

  2. MUST NOT - This phrase, or the phrase "SHALL NOT", mean that the definition is an absolute prohibition of the specification.

  3. SHOULD - This word, or the adjective "RECOMMENDED", mean that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course.

  4. SHOULD NOT - This phrase, or the phrase "NOT RECOMMENDED" mean that there may exist valid reasons in particular circumstances when the particular behaviour is acceptable or even useful, but the full implications should be understood and the case carefully weighed before implementing any behaviour described with this label.

  5. MAY - This word, or the adjective "OPTIONAL", mean that an item is truly optional.  

Let's look at a simple example of how these key words can be used in practice. Although I don't have grass in my own garden, I found a simple article on "How to mow grass like a pro" with some straight forward instructions on - you guessed it - how to mow a grass like a pro to make it truly look slick. Here is the adapted version that uses the key words to emphasize certain points on what to do and what not to do:

  1. The lawn MUST NOT be wet before mowing grass. Being wet only causes grass to clod up and create mounds of grass through out your lawn. When cutting grass when dry; the clippings spread out evenly, and fall into the lawn and disappears. Of course this depends on how high the grass is before cutting. If grass is exceptionally high, you SHOULD bag the grass and dispose of it.

  2. You MUST NOT cut grass too short. Mowing grass too short allows you to possibly scalp the ground and leave dead spots. As a safe measure, you SHOULD cut grass at about 2 1/2 to 3 inches to be safe. Some even prefer 3 1/2 inches. Depending on how level the ground is; if there are unlevel mounds and drainage trenches, you SHOULD consider cutting as high as possible to avoid scalping.
  3. You SHOULD mow grass before weed eating or trimming. 
  4. This will enable you to make sure you will not have to go over the lawn twice. By weed eating after you mow; those corner spots will stick out like a sore thumb, and you will be able to do a more professional job and not miss anything.

  5. A choice of weed killer can be a number of brands. When you choose a weed killer, you MUST be sure you mix it properly. You MUST read the instructions on the label for mixing it correctly. You MUST NOT spray if the wind is 10 mph or above. You MUST NOT spray around young shrubs and flowers, large trees will handle these weed killers, but take precautions anyway.

  6. You SHOULD spray around your home and barns or storage sheds. You SHOULD spray about 3 inches wide. This will look neat and will not leave a wide dead space that is ugly. You SHOULD NOT spray weed killer in drainage areas on your property, this will only cause erosion eventually. You MAY spray ditches but be advised to only spay the very bottom, you MUST NOT spray the sides.

  7. You MUST use an edger for your side walks and walk ways. You MUST NOT spray these areas or even weed eat them. This will only cause the edge of the grass to get wider, and will not look professional. Edging these areas will have a neat straight look

This looks like overkill, but by using the key words, you make sure that no misinterpretation is possible. Although using the key words does not prevent you of adding arguments or elaborate some parts in the document to clarify things. The key words are there to make sure the requirements are well understood.

All guidelines I write now are superseded by a chapter (eg. "Keywords to indicate requirement levels") describing the above key words. Throughout the whole document, I apply the key words consistently to emphasize requirements in the document. The key words are also in uppercase to even emphasize them more.

It is now much easier to write more to the point and stricter guidelines, without sounding arrogant. By describing the rationale behind the key words in a introductory chapter, they are perceived as a formal part of the document and not as me pointing with a finger.

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