The COSMIC Method

COSMIC is a size metric (see Methods for measuring the Size of Software) defined by the standard ISO/IEC 19761. The method is conformal to the standard for Functional Size Measurement (ISO/IEC 14143) and thereby it considers the use cases of a system (similar to the Function Point Analysis).

Objects to be counted by the COSMIC method

COSMIC uses an own definition of actors, the so-called "Functional Users", which can be - additionally to human users and external systems - any hardware or software components sending data to the software to be measured across the system boundaries and thereby triggering a functional process, or receiving and processing data from a functional process of the software. Depending on the direction these data movements are called "entries" or "exits". Additionally, the method counts accesses to data elements which are stored in the database ("read" or "write" operations) and related to the functional processes.

An advantage of the COSMIC method is that it counts data elements directly instead of larger data structures or elementary processes as the Function Point Analysis does (see also Is the Function Point Method still up-to-date?). Another advantage is that regarding the database it considers data movements performed by the functional processes, i.e. read and write operations, and not the static size of the database. These characteristics along with the broad definition of "Functional Users" makes COSMIC suitable for measuring the functional size of real-time systems.

A disadvantage can be that all entries, exits, reads and writes have the same weight and therefore differences in the complexity of their pre- or post-processing can not be considered.