TABLE OF CONTENTS Up until this point we have had very little discussion of the costs of certain features that customers may wish to include in the system requirements. Part of the reason is that it made sense to separate that very complex issue from all of the other problems surrounding requirements elicitation, analysis, representation, validation, verification, and so on. Another reason for avoiding the issue is that it is a tricky one.
There is a fundamental relationship between time, cost, and functionality. Project managers sometimes refer to this triad as the three legs of the project management stool. That is, you can't tip one without affecting the others. For example, you have already finished writing and agreeing the specification and have provided an estimated cost to complete in response to some RFP (request for proposal). If the customer asks you to incorporate more features into the system, shouldn't the price and estimated time to complete increase? If not, then you were likely padding the original proposal, and the customer will not like that. Conversely, if you propose to build an agreed-upon system for a price, say $1 million, and the customer balks, should you then respond by giving her a lower price, say $800,000? Of course not, because if you lower the price without reducing the feature set or increasing the time to complete, the customer will think that you gave her an inflated price originally. The correct response, in...
