1. Project Estimation
Estimation determines how much money, effort, resources, and time it will take to build a specific system or product
The software team first estimates
The work to be done
The resources required
The time that will elapse from start to finish

2. Important for Estimation
What quality is required
How many defects are acceptable after release?
How many defects do we need to find?
What is our team size
What is our team productivity (do we know?)
How many hours is the team is available to work on this project per day? 6? 8? 10?
Are vacation days scheduled?

3. An Estimator uses Product Specs (size only) Team Size (size  effort)
PSP uses a team size of 1
Hours available per day for work (effort  schedule)
Days off (effort  schedule)

4. Estimation Formula Effort in hours How do we find the size of specs?
Size of Team
How do we find the size of specs?
Only two ways accepted as better than guessing!
Function Points
Lines of Code using PROBE in the PSP

5. Observations on Estimation
Planning requires technical managers and the software team to make an initial commitment
Process and project metrics can provide a historical perspective and valuable input for generation of quantitative estimates
Past experience can aid greatly
Estimation carries inherent risk, and this risk leads to uncertainty
The availability of historical information has a strong influence on estimation risk

6. Observations on Estimation (continued)
When software metrics are available from past projects
Estimates can be made with greater assurance
Schedules can be established to avoid past difficulties
Overall risk is reduced
Estimation risk is measured by the degree of uncertainty in the quantitative estimates for cost, schedule, and resources
Nevertheless, a project manager should not become obsessive about estimation
Plans should be iterative and allow adjustments as time passes and more is made certain