Decompose tasks to inch-pebble granularity. Inch-pebbles are miniature milestones (get it?). Breaking large tasks into multiple small tasks helps you estimate them more accurately, reveals work activities you might not have thought of otherwise, and permits more accurate, fine-grained status tracking. Select inch-pebbles of a size that you feel you can estimate accurately. I feel most comfortable with inch-pebbles that represent tasks of about 5 to 15 labor-hours, or about one to three days in duration. Overlooked tasks are a common contributor to schedule slips, so breaking large problems into small bits reveals more details about the work that must be done and improves your ability to make accurate estimates.
You can track progress based on the number of inch-pebbles that have been completed at any given time, compared to those you planned to complete by that time. Defining the project’s work in terms of inch-pebbles is an aid to tracking status through earned value analysis [Lewis, 2000]. The earned value technique compares the investment of effort or dollars that you’ve made to date with progress as measured by completed inch-pebbles.
Adapted from “Practical Project Initiation: A Handbook with Tools” (Microsoft Press, 2007). A condensed version of this paper was published in Software Development magazine.
Karl Wiegers, Ph.D., is Principal Consultant with Process Impact, a software process consulting and education company in Portland, Oregon. Karl’s most recent book is “Practical Project Initiation: A Handbook with Tools.” Karl is also the author of four other books and 170 articles. Karl is a frequent speaker at software conferences and professional society meetings. You can reach Karl through www.projectinitiation.com or www.processimpact.com.