ABSTRACT
Figure 1 presents only the general image of a much more detailed and snarled process. First, there are numerous factors operating at each phase. Second, as the two-way arrows imply, it is not a linear process but rather one in which events at one phase can feed back to alter decisions made at previous stages, which then proceed to work their way through in a continuous interactive way. For example, a decision at the initiation phase to use a specifi c programme may be substantially modifi ed during implementation, and so on.
