- Note that there are mainly two kinds of relevant estimates: schedule estimates and effort estimates. Some tasks will require a certain amount of time, no matter how large the team is.
- Estimates are often not accurate, but they are still very important. An estimate is almost always much better than no estimate.
- Slice the work into smaller parts and try to estimate these separately.
- Use data from earlier work to see how long similar tasks have taken and use that as the base for the estimate.
- If the estimate is difficult, try to at least estimate a range. "3 to 10 hours" is a much better estimate than "I have no idea".
- Estimating skills improve with practise. Observe how accurate the estimates have been and refine your estimates.
- Take risk into account by estimating the probability of the risk and the amount of effort required by the risk. Multiply the effort by the probability of the risk and add it to the estimate
More information
Literature
- Pragmatic Programming (Chapter 2.13. "Estimating")
- Rapid Development (Chapter 8. "Estimation")
