-Unfortunately, extracting requirements from these sources is not - -2
-a straightforward task, as there are many issues involved - -3
-with the requirements elicitation. One first problem is the - -4
-thin spread of domain knowledge. Knowledge is rarely available - -5
-in an explicit form, that is, it is - -6
-almost never written down. Moreover, knowledge is often distributed - -7
-across many sources. For example, in the graphical depiction - -8
-here, to find out that this is the purpose - -9
-of the project. The developer, the analyist, needs to talk - -10
-to a lot of different people. And, to make things even - -11
-worse. There are often conflicts between the knowledge gathered from - -12
-different sources. A second issue is the fact that the knowledge - -13
-is often tacit. What is also called the say, do - -14
-problem. In the example shown here. For instance. We have a - -15
-customer that is describing to the analyst. The way in which - -16
-he accomplishes a task. So it performs these three steps and - -17
-reaches the goal. Whereas in practice, the actual way in - -18
-which this task accomplished is by going through a larger number - -19
-of steps to get to the same goal. So the point - -20
-here is that, even if the knowledge were more concentrated, so - -21
-not as spread as in this example. People simply find - -22
-it hard to describe knowledge that they regularly use. So it - -23
-is hard to make this knowledge explicit, to pass this knowledge - -24
-to someone else. Yet another - -25
-problem is limited observability. Identifying requirements - -26
-through observation is often difficult as the problem owners might be - -27
-too busy to perform the task that we need to observe. - -28
-Or they might be doing a lot of other things together - -29
-with the task that we need to observe, so that becomes - -30
-confusing. That introduces noise. Moreover, even when this is not the - -31
-case, the presence of an observer might change their problem. It - -32
-is very typical for human subjects to improve or modify an - -33
-aspect of their behavior, which is being experimentally measured in response - -34
-to the fact that they know that they're being studied. You know - -35
-that somebody's studying you and you change the way in which you behave. - -36
-A typical issue. Finally, the information that we collect might be biased. - -37
-For several reasons. People might not feel free to tell you what you - -38
-need to know. Or, people might not want to tell you what - -39
-you need to know. For example, in all the common cases in which - -40
-the outcome might effect them, people might provide you a different picture - -41
-from the real one. In order to influence you. So, they might have - -42
-a hidden agenda, and mislead you, either - -43
-consciously or unconsciously. So, all these issues - -44
-add to the complexity of collecting requirements, - -45
-of identifying the purpose of a system. -- cgit 1.4.1