COCOMO (constructive cost model) is a widely used software cost estimation model introduced by Barry Boehm. It uses three sizing methods - object points, function points, and lines of code - to estimate project effort. The COCOMO application composition model uses object points, which are calculated based on the number of screens, reports, and components in an application weighted by complexity level. Estimated effort is then computed by dividing the new object points (adjusted for reuse percentage) by the productivity rate determined by developer experience and environment maturity.

1. P R E PA R E D B Y: A S S I . P R O F E S S O R S E J A L
J A D AV
COCOMO

2. Q. COCOMO (constructive cost model) or algorithm
methods.
• barry boehm introduced a hierarchy of software estimation
models bearing the name COCOMO for constructive cost
model.
• The COCOMO model became one of the most widely used and
discussed software cost estimation models in the industry.
• Like all estimation models for software, the COCOMO models
require sizing information.

3. • Three different sizing options are available as part of the model
hierarchy:
1) object points,
2) function points, and
3) lines of source code.
• The COCOMO application composition model uses object
points.
• Like function points the object point is an indirect software
measure that is computed using counts of the number

4. (1) screens (at the user interface)
(2) reports and
(3) components likely to be required to build the application.
• Each object instance is classified into one of three complexity
level(simple, medium, complex).
• Once complexity is determined, the no of screens, reports, and
components are weighted according to the table shown below.
• When component based development or general software reuse is
to be applied, the percent of reuse (%reuse) is estimated and the
object point is adjusted.

5. NOP = (object points) * [(100-%reuse)/100]
Where NOP is defined as new object points.
To determine an estimate of effort based on the computed
value of NOP value a productivity rate must be derived.
PROD=NOP / person-month.
• For different levels of developer experience and development
environment maturity.
• Once the productivity rate has been determined, an estimate of
project effort is computed using
Estimated effort = NOP / PROD