The COSMIC method provides a standardized way of measuring a functional size of software. In practice, it is at times sufficient or necessary to approximate a functional size :
• when a size is needed, but there is insufficient time or resources to measure using the standard method;
• early in the life of a project, before the Functional User Requirements (FUR) have been specified down to the level of detail where the accurate size measurement is possible;
• when the quality of the documentation of the actual requirements is not good enough for accurate measurement.
The intended audience for the Practitioners Guide is for those who need to establish the size of a piece of software without time or details available to use the standard COSMIC method. For those who are interested in a more in-depth view of the COSMIC approximation techniques, see the Experts Guide that discusses their pros and cons, and their recommended areas of application.