Task analysis is often used during conceptual design to help generate possible solutions. However, it may also be employed during the definition phase to assist in the elaboration of requirements, or when evaluating the capability requirements for an existing product.

Functional analysis provides a means for expressing the problem (without specifying a particular solution) and provides a graphical way to view these requirements. It encourages the designer to trace through each function of the product, making it more likely that all functional requirements will be captured.

Functional analysis is used to break down system-level goals into smaller components, each of which can then, if appropriate, be broken down further. There are many approaches to functional analysis, however, the Functional Analysis System Technique (FAST) has proved particularly useful for product design.

The FAST approach encourages users to define high level functions that need to be accomplished on the left hand side of the page, then progressively identify sub-functions by adding further boxes to the right of each high-level function. The following pages explore

• Tips for functional analysis
• Lifecycle analysis