By Ramiro Rodrigues
The term path is used for a sequence of activities that are serially related to each other.
Imagine, for example, that your colleagues have decided to organize a barbecue. After dividing up the work, you are responsible for hiring the catering services. For this task, you are likely to have to look for recommendations, check availability and prices, analyze the options and then choose the best one. These four activities are a path. In other words, they are a sequence of activities that must be carried out sequentially until a final goal is achieved.
A project manager’s job is to estimate the duration of each planned activity. And if we return to our example, we could consider the possible durations:
- Activity 1: Seek professional recommendations—three days
- Activity 2: Make contact and check availability and prices—six hours
- Activity 3: Analyze the options—one day
- Activity 4: Select the best option and confirm—two hours
This sequence of activities will last 40 hours, or five workdays. And since the whole barbecue has been divided among various colleagues, other sequences (or paths) of activities—such as choosing the venue, buying drinks, organizing football, etc.—will also have their respective deadlines.
The critical path will be the series of activities that has the longest duration among all those that the event involves.
Let's imagine that the longest path is precisely this hiring of the catering services. Since the process is estimated to take five days, the barbecue cannot be held at an earlier time. And if it were held in exactly five days, all the activities involved in the path have no margin for delay. This means that if, for example, my analysis of options is not completed on the date or within the duration planned, then the barbecue provider will not be selected in time, which will invariably lead to the postponement of the barbecue—and leave a bad taste in my co-workers' mouths.
Under the critical path method, there is no margin for delay or slack. If there is a delay in any activity on that (critical) path, there will be a delay in the project. At the same time, other "non-critical" paths can withstand limited delays, hence the justification of the term.
It is the duration of this path that is setting "critical" information for all projects—when all the work will have been completed.
Do you use the critical path method in your work? If so, what are your biggest challenges?