Top-down strategy
In real world problems the dominant situation is non-determinate i.e. where there is no solution that is likely to fully satisfy the requirements. (For examples of non-determinate contexts see: To Engineer (page 5) and The discipline of critical thinking (page 2).
In such situations the basic, top-down, strategy is: propose a possible solution and assess whether it will be satisfactory - or more generally: identify a set of proposals and find the most appropriate one to use.
An internet search on ‘design process’ or ‘problem solving process’ will give a lot of hits but the processes will all be essentially the same. This is because they refer to the top-down strategy that follows logically from the need to assess proposals.
Figure 1 shows fundamental activities in the top-down process:
- Inception where information about the context is gathered and a requirements statement is drawn up. Proposals are assessed against the requirements and it is therefore essential that they are appropriate.
- Conception where options are identified, assessed against the requirements and a decision is made as to the option to by used.
- Production where the solution is developed and implemented
- Review and revise The process is not normally linear. It is kept under constant review and, although ‘getting it right first time’ is a goal it often necessary to backtrack sometimes to a plan B.
How much resource should be allocated to these activities depends on the level of risk involved.