Each week, project management veteran Tom Mochal provides valuable advice about how to plan and manage projects. Tom first describes a common problem scenario, based on real-life situations, and then offers a solution using practical project management practices and techniques.

My team and I are getting pretty good at estimating how much work is involved in a project. However, where we still fall down is estimating how long it will take to do that work. For example, it takes much longer than one day to do one day’s worth of work, by the time you allow for interruptions, phone calls, technical problems, and so on. What we need is a “reality factor” that we can multiply by to give us the duration of a task, given the amount of work to be done. Do you have any magic numbers?



You are right. If you have an activity that you estimate will take forty hours of effort, it is unlikely that it can be completed in five eight-hour calendar days. There are many additional work and personal activities to factor into the estimate as well.

Without taking these into account, it is likely that you will hit your estimates for effort hours but run over your duration estimates. When you are creating an estimate, always determine the effort hours first. Then, keep the following steps in mind to convert the effort hours to the actual duration or calendar days of work.

  1. Start by determining how many productive hours per day a person is actually going to work. There are normal nonproject activities that come up during the day that need to be considered. These include: departmental meetings, social conversations with coworkers, doctor’s appointments, sick time, administrative activities, restroom breaks, etc.
    You could try to come up with the number of productive hours per day your specific team works, but it would be very tedious. A generally accepted ballpark number for average productive hours per day is 6.0 to 6.5, based on an eight-hour day.
    This does not mean that in any one day a person may not be productive for the full eight hours. However, it does factor in a person’s productive hours per day over time.
    For example, in a 40-hour week, one of your team members may have a one-hour department meeting, spend three hours socializing, leave two hours early one day for a doctor’s appointment, spend one hour on administrative requests, spend one hour on the phone for nonbusiness reasons, and spend one hour for restroom breaks (12 minutes per day).
    So during that week, the person was available for 31 hours, or six hours and twelve minutes per day.
  2. Determine how many resources will be applied to each activity. Obviously, two resources may be able to complete an activity faster than one person but maybe not twice as fast. Similarly, a third person may allow the task to be completed sooner but not in one-third the time.
    At some point, adding resources will not make the activity complete any sooner and in fact, may make it go longer.
  3. Factor in available workdays, taking into account holidays, vacations, and training. This was not included in the productivity factor in the first point, since this nonproject time can be scheduled and accounted for in advance. For example, on a three-month project, one team member may be out for two holidays, while another may also have ten days of vacation.
  4. Take into account any resources that are not full time. If you have a resource 50 percent of the time, it will take them at least twice as long to do any individual activity.
    But also look at the type of nonproject work they are performing. If a team member has a 50 percent block each day, or can work 20 hours in a row per week, they will be more productive than a person who works 20 hours a week but is constantly being interrupted from a half-time support role.

Share with the team what the assumptions are for each person. Let them know your scheduling assumptions for them and why you are expecting that.

They then have the responsibility to tell you if outside influences are making it difficult for them to spend the allotted time on the project. That will give you the input you need to change their work responsibilities or else change their availability factor.

Project management veteran Tom Mochal is director of internal development at a software company in Atlanta. Most recently, he worked for the Coca-Cola Company, where he was responsible for deploying, training, and coaching the IS division on project management and life-cycle skills. He’s also worked for Eastman Kodak and Cap Gemini America and has developed a project management methodology called TenStep.

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