Theory of Constraints Handbook - James Cox Iii [99]
Figure 6-11 demonstrates the amount of a particular resource’s time budgeted to the project versus the actual need for that resource, creating an inventory of available hours that will be used by the project but not necessarily drive value.
The fifth category of waste is excess motion. Excess motion occurs in projects when time is taken on a task that is not inherently needed to accomplish the task to create value. Holding onto a task that is complete and continuing to polish the output or searching for a handoff from a predecessor task are all excess motion. Additionally, when a task is multitasked, time is required for setting the task down and/or picking it back up. This time is all non-productive from the task’s viewpoint and is therefore waste (Fig. 6-12).
The sixth category of waste is non-value-added processing. This category can include inserting excessive or redundant reviews and sign offs. It also includes the situation where resources are required to accomplish additional tasks within the project that are not part of the project, but that are included because the resource may be in a similar area of work (Fig. 6-13).
This happens frequently in software development projects where, in making a change in a part of the operating program for the project, the resources are asked to update the programming in the same part of the code for an additional need that is not associated with creating value for the project at hand.
FIGURE 6-11 Excess inventory. ©1991–2010 Avraham Y. Goldratt Institute, LP. All rights reserved.
FIGURE 6-12 Excess motion: Unnecessary set up and set down of a task. ©1991–2010 Avraham Y. Goldratt Institute, LP. All rights reserved.
FIGURE 6-13 Non-value-added processing. ©1991–2010 Avraham Y. Goldratt Institute, LP. All rights reserved.
The seventh category of waste is defects. Defects can take many forms, from wrong, missing, or incomplete information to handing off a task that does not meet its exit criteria. The defects category also captures the situation when variability is not addressed in the project when it first occurs. The later the variability is discovered, the more time and task areas will have to be reworked, creating waste of time (Fig. 6-14).
The eighth category of waste is underutilized resources. In many project environments, within the same skill set, there are “go-to” people. Everyone wants them on their tasks and in their reviews.
In Fig. 6-15, the load for the two blue skilled resource is 100 percent, but when we look at the load by individual person, one is loaded 170 percent, while the other is loaded only 30 percent and is underutilized.
Pursuing Perfection
The fifth principle of Lean that Womack and Jones (1996) cite is the pursuit of perfection. Lean practitioners are asked to visualize the “perfect” process. No matter how much you improve a process to make it leaner, there are always ways to continue to remove waste by eliminating effort, time, space, and errors. There are six key ways to pursue perfection in projects. They are
1. Address variability at the earliest point in the project.
2. Plan how you desire to do the project (not the way you think will fit or have always done it).
FIGURE 6-14 Not resolving variability. ©1991–2010 Avraham Y. Goldratt Institute, LP. All rights reserved.
FIGURE 6-15 Underutilized people. ©1991–2010 Avraham Y. Goldratt Institute, LP. All rights reserved.
3. Don’t commit to a work-around until you see if one is needed (or can check for any negative consequences of the work-around).
4. Template best project practices into a PERT or network diagram and use for all like projects.
5. Apply project-based risk