As part of my Master’s Degree I’ve chosen to study a Project Management module, I’m not really into project management, but as a freelancer I have to work with others and occasionally need to bring other freelancers on-board where a project doesn’t entirely fit within my own skillset, so project management fits.

I found a recent topic on the module interesting, and I though it was worthwhile talking about. The topic…Schedules with limitations.

According to the module material, a project would be broken down into its various tasks, usually in the form of a work breakdown structure (WBS). The WBS is a top-down approach that groups/lists activities within a project, which can then be used to assess estimates and risks.

At some point during the project, resources need to be assigned to tasks, and this is where I found things starting to get interesting. Take the following list of activities as an example, it lists activities, how many staff are allocated, how many weeks it will take and it’s dependencies;


Activity Name Staff Duration (weeks) Dependent on
A 2 10 none
B 2 10 A
C 1 10 none
D 1 10 none
E 1 10 B, C and D
F 1 5 D
G 2 5 B, C and D


Using the information in the table above, we can produce what is called a resource loading chart, it shows the allocation of resources across the project. I’ve quickly put together the following chart, based on the project having a maximum duration of 30 weeks.

What the chart aabove  tells us is that based on the information in the table, we need 4 staff to complete the project in the allocated time of 30 weeks. The spacing between activities in the chart is called float, if we use activity D as an example, the float allows the activity to be worked on anytime between weeks 0 and 20, providing that it is finished at the end of week 20 so that it doesn’t hold up other activities which depend on it. Activities F and G also have float.

The chart above is unsmoothed, that is, it’s our initial chart, and further improvements can be made. If we were to assume that all staff on the project were interchangeable, then we have some flexibility as we can assign more or less people to an activity at a given time if it benefits the project as a whole. For example, activity D in the table requires 1 person and 10 weeks, but, if we were to assign it 3 people, then it’s duration would reduce. Based on this flexibility, we can rework the chart to look like this;

In the chart above, you can see that we’ve allocated more resources to activities D, G and E, taken those resources from other tasks. In doing so, we’ve extended the duration of the project to around 31.5 weeks, but have also reduced the maximum resource load from 4 people to 3. Think of this process a little like playing Tetris, you’re trying to fill the gaps within the constraints of the project (duration, resources).

The most interesting point of this topic is what happens if we place a 2 resource limit on the project, for example, you’ve been given a project and you’re been allocated two people to work on it rather than three. I worked out that the activities listed above would take 60 weeks to complete (instead of around 30), and cost 30% more in staff costs with only two staff, than it would if the project was allocated three staff.

The key point I’m trying to make is that great care needs to be taken when allocating resources to a project. In my example above, it could be assumed that if a project takes 3 people 30 weeks to complete, then it should take 2 people 50 weeks to complete, but due to dependencies within the project, it’s actual duration is closer to 60 weeks. If every member of staff was paid £20 per hour, three people would be paid a total of £67,500 over 30 weeks. In comparison, two people would be paid £90,000 over 60 weeks. Adding just one more person to the project could make it way more profitable.