Since estimating efforts cost money, the time and detail devoted to estimating are important decisions. Yet when estimating is considered, you as a project manager may hear statements such as these:

• Rough order of magnitude is good enough. Spending time on detailed estimating wastes money.
• Time is everything; our survival depends on getting there first! Time and cost accuracy is not an issue.
• The project is internal. We do not need to worry about the cost.
• The project is so small. We do not need to bother with estimates. Just do it.

However, there are sound reasons for using top-down or bottom-up estimates.

In a well-constructed initial response utilizing the knowledge you gained from the initial readings as well as your own experiences, discuss the following questions:

• What are the differences between bottom-up and top-down estimating approaches?
• Under what conditions would you prefer one over the other? Provide an example.