As we saw in the last module, the writing of good requirements is essentially about removing the ambiguity from the resulting statement. We first identified a suitable structure for the statement and we then began to look at the rules that we should keep in mind when writing requirements. In this module we continue to move through the rules, particularly as they relate to the use of vague and superfluous words.

In the last module we addressed more of the rules we need to follow in order to develop good requirement statements. In particular we looked at the rules that relate to the use of vague and superfluous words. In this module we address more of those rules, starting with some more rules about other words we should avoid when writing requirements. In particular, we look at avoiding conjunctions unless we introduce a formal convention for logical conditions. We also discuss why we must avoid unbounded statements and escape clauses.

In Module 4, we complete our look at the rules for writing requirements. In particular, we focus on when we should and should not be precise; how to use units, ranges and tolerances; and some final things to avoid (such as cross-references, including pronouns, and the use of “not” in forming negative requirements).

This final module allows you some time to revise the first four modules and the quizzes in order to prepare for the completion of the course exam. The exam questions are drawn from the same large pool of questions as the quizzes—so you should not be surprised by the test questions since you will have seen something very similar if you have prepared by completing the quizzes a sufficient number of times. We also provide some addition information regarding the Master of Systems Engineering program at UNSW Canberra.