Page 140 - DCAP304_DCAP515_SOFTWARE_PROJECT_MANAGEMENT

Software Project Management

Notes Detractors of Symons’ work say that MK II is simply a way to overstate the value of the monolithic
systems that Nolan, Norton & Co.’s clients were building at the time. They consider it a political
concession that will undermine the competitiveness of those clients in the long run. More
moderate critics believe that Symons identified some function point issues that practitioners
were already addressing. However, he chose to deal with them in a manner that would lead to
a proprietary Nolan, Norton & Co. product, instead of strengthening the original Albrecht
work.
Grant Rule supplied information on the current state of MK II. He reported that the technique
has been in the public domain since 1991. The design authority is the United Kingdom Software
Metrics Association (UKSMA) who were formerly known as the United Kingdom Function
Point Users Group (UFPUG).

6.7 COCOMO Model

Constructive Cost Model (COCOMO) is a method for assessing the cost of a software package.
COCOMO, Constructive Cost Model is static single-variable model. Barry Boehm introduced
COCOMO models. There are three levels of COCOMO model basic, immediate and detailed.

6.7.1 Brief Characteristic of the Method

 COCOMO (Constructive Cost Model) is a combination of parametric estimation equation
and weighting method. Based on the estimated instructions (Delivered Source Instructions
DSI), the effort is calculated by taking into consideration both the attempted quality and
the productivity factors.

 COCOMO is based on the conventional top-down programming and concentrates on the
number of instructions.

6.7.2 Levels of Model

 Basic COCOMO: Basic COCOMO model is static single-valued model that computes
software development effort (and cost) as a function of program size expressed in estimated
lines of code. By means of parametric estimation equations (differentiated according to
the different system types) the development effort and the development duration are
calculated on the basis of the estimated DSI. The breakdown to phases is realized in
percentages. In this connection it is differentiated according to system types (organic-
batch, semidetached-on-line, embedded-real-time) and project sizes (small, intermediate,
medium, large, very large).
 Intermediate COCOMO: Intermediate COCOMO model computes software development
effort as a function of program size and a set of “cost drivers” that include subjective
assessments of product, hardware, personnel, and project attributes. The estimation equations
are now taking into consideration (apart from DSI) 15 influence factors; these are product
attributes (like software reliability, size of the database, complexity), computer attributes
(like computing time restriction, main memory restriction), personnel attributes (like
programming and application experience, knowledge of the programming language), and
project attributes (like software development environment, pressure of development time).

Notes The degree of influence can be classified as very low, low, normal, high, very
high, extra high; the multipliers can be read from the available tables.

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