Guiding your estimates in the right direction

Problem: Estimating effort for (test-)activities is inaccurate

Estimation, or educated guessing is the foundation for many an activity related to management of a project. Given that estimation is not an exact science there will be inaccuracy in the numbers used for planning and resource allocation.

 

Solution: Apply general estimation rules and use a technique to guide your estimates.

In order to improve accuracy in your estimation you can rely on some general estimation rules and use a technique to guide your estimation.

General estimation rules:

·         A full-time resource will only be productive around 80% of the time.

·         Shared resources, working on multiple projects will have a lower productivity given that they will have to spend time when they do context switching.

·         There is a high degree of optimism in estimates, as most people have tendency of underestimating complexity and time consumption.

·         Base you estimates on multiple sources – Don’t just use own experience, pursue experience of others if possible.

·         Estimation of a task should be done by the person/team responsibility for doing the task.

·         Remember to include issue management, meetings and other supportive activities in the estimate.

·         Break estimates down if possible.

·         Make sure that assumptions, exceptions and limitations are clearly documented as part of the estimate

Techniques for estimating

·         Top-down estimation

·         Bottom-up estimation

·         Combined top-down & Bottom-up estimation

·         Comparative estimation

·         Parameter estimation

·         One-point estimation

·         3-point estimation

·         …

The point is that there are numerous techniques that allow you to do more or less scientific estimation – You need to choose the one that fits the purpose and tolerance of your project.

Happy testing!

/Nicolai