Estimation overview
Estimating model
An estimating model is a way of calculating estimates. An estimating model can use any number of estimating factors. Possible estimating models might be:
- Use Case estimating: Uses the number and complexity of use cases to estimate effort.
- Multi-factor: Uses several aspects of a project to estimate effort.
Estimating factor
An estimating factor is something that has a quantitative influence on the effort required to perform a task or activity.
Possible estimating factors are:
- For Use Case estimating:
- Complex use cases
- Medium use cases
- Simple use cases
- For Multi-factor estimating:
- Business areas
- Platforms
- Screens
- Classes
- Use Cases
Estimating formula
An estimating formula defines a way to calculate a value for an estimate using estimating factors.
In this first release you can:
- Associate one or more estimating factors with a task or activity.
- Select a calculation formula to use for each estimating factor.
- Calculate an estimate based on each individual estimating factor.
- Sum the estimates for a task or activity .
- Sum the estimates for activities to higher level activities.
Bottom-up estimating
Engineering Method Composer provides a 'bottom-up' estimating approach. Estimates are created for tasks in a work breakdown structure (WBS) for a project and summed through the WBS to arrive at an estimate for the whole project.
The process can be summarized as follows:
- Create an estimating model.
- Create estimating factors for that model.
- Assign estimating factors to tasks.
- Adjust estimating formulae for task descriptors.
An alternative is to create estimates at an intermediate level in a work breakdown structure and sum to the project level from there.
Adding estimating information
Estimating information is held separately from other information in a library. In this release, estimating information is not subject to the method plug-in locking mechanism in a library. You can add estimating information to tasks and processes in unlocked or locked method plug-ins.
If you want to create your own estimating model for RUP tasks and processes, you can do this directly in the method plug-ins in the library.
You can also add estimating factors to a task using a contributing task.
Exporting estimates to a project scheduling tool
Effort estimates can be exported along with the process to Microsoft Project or Rational® Portfolio Manager.
In the export wizard you can:
- Choose to export effort estimates for work breakdown elements.
- Choose the estimating model that you want to use. You must have calculated the estimates before exporting.
If you choose to export only breakdown elements that are planned, and you have the planned flags set for activities but not tasks, activity estimates will only be exported if the estimates are calculated at the activity level. Summed estimates for the activities will not be exported.