An effective means of controlling model developments is to pre-define as much of the work as possible, thus reducing later risks and reducing the likelihood of time being wasted on blind alleys etc. The purposes of the Technical Design are therefore to:

1) identify the full range of tasks needed to develop the model,

2) describe each task in as much detail as possible, in this process seeking to constrain the analysis to preferred/expected outcomes, and

3) anticipate risks.