The most popular algorithmic cost estimation model for software projects is the Constructive Cost Model (COCOMO II), developed by Barry Boehm and Ellis Harrowitz in 2000.
The basic COCOMO'81 model is a simple static model that considers the software development cost as a function of a program's size expressed in estimated lines of code.
The intermediate COCOMO'81 model computes software development cost as a function of program size and a set of four subjective cost drivers: product factors, computer factors, constraints, and personnel factors. Product factors include aspects such as required reliability, complexity, usability, size of database, and more. Computer factors include constraints such as execution time, storage, turnaround, and platform volatility. Personnel factors include capability of the analyst, application, language, and tool experience, personnel continuity, and more. Project factors include multi-site development, software tools and more.
The detailed COCOMO'81 model incorporates all characteristics of the intermediate version and also incorporates an assessment of the cost driver’s impact on each step of the software engineering process.