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.