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Literature Review COCOMO II Investigation
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Literature Review COCOMO II Investigation COCOMO_investigation.doc

Version: 0.1 Date: 29/April/2005

Revision History
Date 29/April/2005 Version 0.1 Description This is just first literature review about COCOMO II. The main resource is the book, cf. reference section. Author Hawk Wang ( )

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Literature Review COCOMO II Investigation COCOMO_investigation.doc

Version: 0.1 Date: 29/April/2005

Table of Contents
1. 2. Introduction COCOMO II models 2.1 General methodology 2.2 Concrete Models - Early Design Model & Post-Architecture Model 2.2.1 Model Formula 2.2.2 Scale Factors 2.2.3 Effort Multipliers 2.3 Model Calibration and Customization 2.4 Model Application GoodPoints for Research Project Summery Reference 4 4 5 6 6 7 7 9 10 11 11 11

3. 4. 5.

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Literature Review COCOMO II Investigation COCOMO_investigation.doc

Version: 0.1 Date: 29/April/2005

1. Introduction
The COCOMO cost estimation model is used by thousands of software project managers, and is based on a study of hundreds of software projects. Unlikeother cost estimation models, COCOMO is an open model, so all of the details are published, including: • • • •
The underlying cost estimation equations Every assumption made in the model Every definition The costs included in an estimate are explicitly stated

Because COCOMO is well defined, and because it doesn't rely upon proprietary estimation algorithms, it has following advantages: • •COCOMO estimates are more objective and repeatable than estimates made by methods relying on proprietary models COCOMO can be calibrated to reflect your software development environment, and to produce more accurate estimates

Now, COCOMO II is the current version of COCOMO model. It is enhanced based on COCOMO 81 model to accommodate different approaches to software development, for example,incremental development. COCOMO II incorporates a range of sub-models that produce increasingly detailed software estimates: • • •
Application composition model. Used in the earliest phases or spiral cycles, which will generally involve prototyping using application composition capability. Early design model. Used in next phases or spiral cycles, which will generally involve exploring architecturalalternatives or incremental development strategies. Post-architecture model. Once the project is ready to develop and sustain a fielded system, it should have a lifecycle architecture, which provides more accurate information on cost driver inputs and enables more accurate cost estimates. Post-architecture model is suitable for such phases.

Generally speaking, COCOMO II can be used for: • • • •• • • •
Software development approach Budget decisions Production tradeoffs IT capital planning Investment options Management decisions Prioritizing projects SPI strategy

Since COCOMO model has a lot of aforementioned advantages, how its approach can be used for our current research work is worth investigating.

2. COCOMO II models
According the applicability, three COCOMO II models areintroduced. Following figure gives an Public ©BeyondTest 2005 Page 4

Literature Review COCOMO II Investigation COCOMO_investigation.doc

Version: 0.1 Date: 29/April/2005

illustration about model applicability. In this documentation, only Early Design Model and Post-Architecture Model are discussed to simplify the contents.

Figure 1 Model Applicability 2.1 General methodology The essence ofCOCOMO II model is non-linear regression modeling. Figure 2 is used to depict such approach.

Size

COCOMO II (Parameters)

Cost Schedule

Factors (Software Platform, Product, Personnel & Project attributes) Figure 2 COCOMO II model illustrations Here, size can be estimated as KLOC or Function Points. In order to estimate system size, four important factors should be considered....