COCOMO Models
It is a heuristic estimation technique. This is also known as constructive Got model. Software development project can be classified into one of the three categories based on the development complexity i.e., organic, semidetached and embedded.
Organic
We can consider a development project to be of organic type, if the project deals with developing a well understood’ application program. The size of the development team is reasonably small and the team members are experienced in developing similar types of project.
Semidetached
If the development team consists of a mixture of experienced and unexperienced staff. Team members may have limited experience on related system but may be unfamiliar with some aspects of the system being developed.
Embedded
We apply this approach, if the software being developed is strongly coupled to complex hardware or if stringent regulations on the operational procedure exist.
According to Boehm, software cost estimation should be done through three
stages i.e., basic COCOMO, intermediate COCOMO and complete COCOMO.
Basic COCOMO Model
Barry Boehm introduced a hierarchy of software estimation models named Constructive Cost Model. Basic equations of COCOMO model are
Efforts in person-months (E) = a (KLOC)b
Development time in months (D) = c (E)d
Where a, b, c and d are coefficients that have fixed values for different classes of projects.