[11] A Truer Representation

One may wonder why so many executives make project commitments that are overwhelmingly optimistic and associated with exceptionally high risk. Consider the next figure, which shows only the 8-task sequence and the accompanying histogram. The histogram suggests that the common practice of making a commitment for what appears the last scheduled day of work, time T1, leads to unacceptably high risk. The probability of completing the 8-task sequence by time T1 is only 50%. Yet, this is precisely what nearly all project managers end up with today. Why does virtually every executive require this obviously wrong approach to estimating project duration?



The reason is provided by a brief scrutiny of our project management software tools. Except for the rarest of cases, every project plan that is created with today’s project management software tools is displayed as a stack of task bars, much like the task bars shown in the above figure, and the histogram never accompanies the display of task bars. Decision-makers see only the task bars with clearly defined starts and ends. Worse, our software tools go so far as to display dates, which appear to coincide unquestionably with the starts and ends of the task bars. Inevitably, this totally deterministic display of erroneous information fools decision-makers into thinking that they and their project managers are capable of causing events to take place on specific dates. Our models of projects, in other words, are consistently and significantly misleading the decision-makers. Hence, the widespread practice today is for decision-makers, project managers, and at times even customers, to participate in what is nothing short of a grand self-deception.

How should information be displayed instead? Consider the next figure. If any event related to a project can be specified at all, that event is the start of the project. This indeed is a deterministic event, as are the starts of all the various sequences of tasks that one finds in a real project. However, once a sequence of tasks is underway, all subsequent task-start events within the sequence and all subsequent task-finish events within the sequence are entirely unpredictable. An appropriate display for a sequence of tasks should not pretend to predict precise times for these events.

A far truer representation is provided by the next figure, which shows a clearly defined edge only at the left-and end of the sequence. All the other task-start events and task-finish events associated with the sequence are omitted from the representation. Further, the color of the task bars is shown steadily and smoothly fading, from left to right, to indicate the increasing degree of uncertainty in our estimates of the downstream events.



The histogram, too, is depicted in a more appropriate manner. Rather than being displayed in solid colors, varying shades of red indicate the increasing risk associated with increasingly optimistic estimates of duration. The right-hand end of the histogram is shown with vanishingly small levels of red, indicating that this portion of the histogram and the corresponding estimates of duration can be associated with correspondingly low levels of risk.

If decision-makers were provided with this sort representation of their projects, their tendency to favor optimistic, high-risk estimates of duration would be greatly diminished. After all, how many ambitious executives would expose their careers to unnecessary risk?

We see, therefore, that the sadly deficient state of project models today is driven by the grossly deficient tools in widespread use. These tools have been designed and developed by people who lack even a rudimentary understanding of variation. The grossly deficient tools are used regularly by project managers whose understanding of variation is equally lacking. Further, the reports created with the tools consistently mislead decision-makers. The erroneous reports regularly lull decision-makers into a false sense of optimism, which exposes them, their businesses, and their customers to inordinate levels of risk.

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