A Tech Log

October 30, 2008

Project Estimation using Use Case Metrics

Filed under: Enterprise & Application Architecture — adallow @ 3:04 am
Tags: ,

FRom EA site:

Enterprise Architect provides a comprehensive project estimation tool that calculates effort from use case and actor objects, coupled with project configurations defining the complexity of the work environment. This method is based on Karner’s Use Case Points Method, with several variations noted below. You can also produce a metrics report containing the project estimation analysis to incorporate into your project documentation. An example is here.

Before estimating project size, you will first need to configure the technical and environmental factors (see menu item Configuration – Metrics and Estimation Types – TCF and ECF values). For both TCF (technical complexity factor) and ECF (environment complexity factor), an editable table contains a list of factors influencing project productivity. A weight is associated with each factor, reflecting how much that factor relatively affects productivity; a weight is irrelative to a project. The supplied factors and their associated weights are defined by the Use Case Points Method, although they may be adjusted to suit a project’s specific needs. For most purposes, the only table column needing adjustment will be ‘Value’, which indicates the degree of influence a particular factor holds over the project. As a suggested gage, a value of ‘0’ indicates no influence, a ‘3’ indicates average influence, and a ‘5’ indicates strong influence.

Karner’s UCP method also calculates project effort by considering project actors, and their contributing complexity. There is an option to include actors in the estimation calculation; by default, only use cases are considered. If project actors are also included, make sure their complexity has been assigned by some method; rough guidelines to this assignment are supplied below:

  • Easy: The actor represents another system with a defined API
  • Medium: The actor represents another system interacting through a protocol, like TCP/IP
  • Complex: The actor is a person interacting via an interface.

Once you have set up the use cases, actors and environment, highlight the package in the project browser whose contents you would like to estimate; for the entire project, select the root view. Next, select Project – Use Case Metrics from the menu. The following screen will appear:



see: http://www.sparxsystems.com/resources/ucmetrics.html


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