Microsoft Project 2007: The Missing Manual

Chapter 5. Estimating Work Time

Once you’ve identified the tasks that comprise a project, the next step is figuring out how many hours or days of work those tasks entail—and the duration to allow for that work. For example, you need to know how long it takes to repair and paint the front of a ’67 Mustang Fastback to figure out whether you can hide the evidence before your parents get home from vacation.

You’ll never predict project performance with total accuracy. However, estimating work time and duration as closely as you can is the goal, because high or low estimates can both cause problems. Overestimate how long your project will take, and the project might get squelched before it begins. Yet underestimating leads to disappointment, extensions, and financial consequences.

In this chapter, you’ll learn about different ways to estimate time and duration, how to improve estimates, and how to avoid estimating landmines. You’ll also learn how to create spreadsheets for collecting estimated numbers from team members, and then import the numbers into Microsoft Project.

Understanding Work and Duration

In Project, work and duration are both ways of measuring project time, but each term has a specific meaning:

Work. The number of person-hours (or equipment-hours) a task requires. For example, packing all your belongings may take you (that is, one person) 20 hours. (Hey, you have a lot of sentimental keepsakes.)

Duration. How long a task lasts. Duration varies according to how many resources ...