Five Common Scheduling Mistakes

Nancy Lea Hyer and Karen A. Brown

Project scheduling is a critical part of the project planning process. If done well it enhances team understanding and perspective, sets and manages expectations, highlights uncertainties, creates a foundation for the monitoring system, and generally helps everyone involved to visualize the action plan. Unfortunately, many teams and individuals make serious mistakes when they create and use project schedules.  Here are five common mistakes we’ve encountered in our work with organizations.

1.  Assuming the plan begins with a schedule

Don’t be fooled! Before a team develops a schedule, members must have established an understanding of the project’s purpose, agreed on goals, selected the best course of action for achieving the goals, created a comprehensive work breakdown structure, and assessed project uncertainties. If a team does not develop this shared understanding, conflicts driven by divergent views of what we are supposed to be doing, how to do it, and what might go wrong will surface at very inconvenient times. The result will be lots of rework and considerable angst.

2.  Not involving the team in creating the schedule, assessing it feasibility, or identifying schedule risks

Project schedules are best created in a team environment. The results are better decision-making about sequencing, a higher commitment to time-based goals, and a more realistic schedule that reflects the team’s collective knowledge about the work that needs to be done, risks, and competing priorities.  When the project manager creates the schedule independently, without team input, it can undermine team commitment and result in a schedule that is disconnected from what is feasible. Moreover, team members may distrust a project manager who does not tap the expertise of those who will be doing the work in developing the schedule. “He doesn’t want our input in planning the project? Fine. He can just deliver the project on his own, too.”

3.  Thinking you can see the big picture on a computer screen

You can’t. For a project of any reasonable size, a team or individual can see only a portion of the schedule on a computer screen. And when you look only at a segment of the plan, you may make decisions not in the best interest of the project overall. A wall-mounted paper schedule display can provide an effective means for visualizing the project in its entirety.  Communication and decision-making will be vastly improved.

Don’t start the scheduling process on a computer!

4. Making time estimates before you lay out the schedule

As we have discovered through our work with a many teams, a team-based scheduling process enables members to clarify the meaning and content of tasks listed in the WBS. It is not until they’ve been through this process that they can accurately estimate times. Additionally, in many cases, activity duration depends on the sequence in which activities are done.  If you make time estimates before sequencing, you may base your schedule on activity durations that either understate or overstate the time required.. We advise teams to lay out the schedule first, then examine individual activities in context to estimate activity times.

5.  Failing to consider resource constraints in the schedule

Resources likely to create constraints include people, materials, services, information, equipment, money and physical space. The team needs to consider these in order to create a realistic schedule.  Teams who overlook resource constraints generate schedules divorced from reality. When teams are unable to deliver on these unrealistic schedules stakeholder dissatisfaction and low team morale are likely. If you create a schedule that does not consider resource constraints, be certain to include the activity, “pray for miracle.”  You will need it.

For more scheduling tips, see Chapter 7 in Managing Projects: A Team-Based Approach