All schedules come with risk, so learning to address some of the more common risks associated is an important step to their mitigation.
Your scope may very well be attainable, but your schedule may transform your otherwise reasonable project into an inevitable failure. Sources of schedule risk include multiple critical paths, multiple predecessor dependencies, procrastinating on difficult efforts, and planning into the distant future. Avoiding schedule risk is worth the effort. And it helps translate a feasible project into a realistic project plan.
This article discusses some of the common risks that can occur in project schedules and tips for avoiding schedule risk.
Reduce the number of Critical Paths
It is not uncommon for project schedules to have more than one critical path, but multiple critical paths increase schedule risk. For our discussion let’s say the probability of an activity finishing on time is the same chance as it finishing late. The project probabilities in this scenario is 50/50. What happens when we have two critical paths? The probability for each path to be on time is the same as the activities, 50 percent.
But we have two critical paths. If the risk associated with the two paths are independent, there are four possibilities. And the project has only one chance in four of finishing on time because both paths must finish on time. The probability of both paths to be one time is therefore 25 percent.
The purpose of this discussion was to explain why schedulers should seek to reduce the number of critical paths. Each additional critical path makes a significant contribution to risk. This exercise also assumed the statistical independence for all events. The reality is that there is significant correlation between project activities. One late activity cascades to make another activity late. Again, multiple parallel critical paths is a risky situation, so look to reduce the number of critical paths.
Reduce Activity Dependencies
Any point of dependency convergence in the schedule increases schedule risk. In this case an activity has multiple predecessor dependencies. This magnifies risk at this juncture because project work stops whenever even one preceding activity is incomplete. Each additional predecessor dependency represents an additional failure mode and increases delay risk. If at all possible, modify the schedule so one activity does not have an overabundance of predecessor dependencies.
Schedule Risky Activities Earlier
The timing of planned work is a risk factor. The tendency is to postpone difficult tasks until later. But procrastinating on particularly challenging efforts is not good. Doing so leads to increased project risk and cost impact. The worst case scenario is finding out your novelty is not feasible and, therefore, the project cancels after months or years of expended effort and cost.
If you had, however, scheduled the high risk activities earlier and learned your invention is not possible sooner the cost incurred of a failed project would be correspondingly less. Scheduling risky activities earlier, allows you to discover showstoppers faster and with less effort. Yes, it’s true that you want an easy project start until ramp up to full momentum, but definitely consider planning your difficult tasks early in the life of the project.
Plan Regular Schedule Reviews
One thing that helped Chuck Yeager become a top ace fighter pilot during WWII was his ability to see far into the distance. He could spot enemy planes before they could locate him. This allowed him to orient his plane in a tactically favorable position to prepare for the ensuing air battle. But even the farsighted, like Chuck Yeager, are limited by how far they can see into the distant horizon. The earth’s curvature is also a limiting factor. Well, like fighter pilots projects and project managers have visibility constraints.
Projects differ in the amount of accurate distant planning that is possible. Some projects are prohibitive to plan beyond even three months in advance. This has led to the popularity of project management methods like Agile that accommodate more fluid or shifting scope requirements. How far can you plan your project into the distant horizon? As a rough guideline, it is difficult to plan most projects out past 6-months.
Uncertainty in work planned too far in advance is a significant source of schedule risk. To help avoid distant project planning risk insert regular activities in the project plan to review estimates, risks, and assumptions. Schedule risk management relies on periodic reports and recommendations for project plan adjustments. So plan your project into the distant horizon, but schedule plan reviews on these long duration projects to occur at least every six months.
Summary
Project planning comes with schedule risk. And this schedule risk may be a significant factor in the failure of your project. Look to minimize the number of critical paths to help in avoiding schedule risk. Schedule path convergence is a major risk, so modify the work so a respective activity has fewer predecessor dependencies. Do not delay complex efforts. It is very difficult to see beyond the horizon so avoid scheduling errors by planning regular reviews of your long duration project.
For more insight on managing project risk consider “Identifying and Managing Project Risk” by Tom Kendrick.