8. Understand schedule and resource optimisation

Question 1

Explain two differences between critical path and critical chain scheduling
techniques.

Answer 1

Critical path is focused on the time element of a work package. Each work package will have a defined start time, end time, and duration. The work package should be completed within that allocated time window.

Critical chain is focused on the resource available to complete the work package. The theory is that the work package should be started as soon as possible and finished as soon as possible to the agreed quality level, with the resource available.

The critical path model has no buffer or slack that is purposely built into the model. The tasks are supposed to take the duration stated within the model, no more or less. Conversely the critical chain model reduced the amount of time given to a task, relative to critical path, but creates buffers or slack
within the schedule to soak up any occasions where it is needed. This theory reduces any potential for team members to potentially intentionally delayed starting a package of work. Critical chain has been shown to significantly reduce the duration of real world projects.

Question 2

Describe how three different categories of resource can be allocated in an iterative
life cycle

Answer 2

In an iterative lifecycle the release of funds will be more frequent and in smaller chunks than in a linear lifecycle. This is because the project tasks will be delivered in iterations or timeboxes. At the start of each iteration the project manager will work with the product owner or sponsor to decide on what can be
achieved and the costs are estimated and drawn down accordingly.

In an iterative lifecycle, the people allocated to each iteration are fixed and within each iteration the people may fulfil multiple roles. If they have completed their own tasks within an iteration, they may pick up on different tasks in order to achieve the iteration’s objectives. Having multi skilled resources
will be useful to the project, it is also good for the individual in as much their own skills expand. Where tasks are outstanding in an iteration, they are returned to the backlog and the scope for the iteration adjusted rather than an increase in the number of people working on the iteration.

In projects where there is a need for the supply of materials to support the scope of work, it is important to have the materials available when they are needed. Likewise, it is not cost efficient to buy in all the estimated materials at the start of the project, particularly in an iterative lifecycle as the scope is less defined. Therefore, the project manager and sponsor/product owner need to review the backlog of scope ahead of time to ensure that the materials to support the work are ordered and delivered in time for the iteration that requires it. By doing this well, there is less waste of materials and less materials sitting around waiting to be used.

Question 3

Question part (a) Describe two elements that need to be considered when allocating resources to a project schedule following a linear life cycle.
Marks 20 marks (10 marks each)

Question part (b) Explain three key differences between resource smoothing and resource levelling.
Marks 30 marks (10 marks each)

Answer 3

Question part (a)

1) Availability – at the start of a project during schedule planning/resource allocation, the project manager may make the assumption that all resources are available for the entirety of the relevant project phases or throughout the project lifecycle. However, it does need to be considered that circumstances can change and if resources become unavailable (for example, if it was agreed that a ‘tester’ was available during the deployment stage but they fall ill and are now unable to provide their services for the project) then corrective measures need to be put in place/corrective actions need to take place. This can be in the form of resource smoothing or resource levelling depending on the situation.

2) Relationship between resources and project logistics – Resources can come in many shapes and sizes including labour (humans) and materials. It is important that the project manager considers the relationship between resources and the project logistics. For example, labour resources (humans) will require space to physically work (e.g. an office space) and that materials/equipment will need space to be stored; considerations that the PM will need to take into account when allocating resources within their project.

Question part (b)

In the process of allocating resources, the project manager can use ‘resource levelling’ or ‘resource smoothing’ to realign the project resource profile. Three differences between these approaches are

1) ‘Resource levelling’ is used when resource availability is limited and time is not an issue – which means the project manager cannot put more resources into the project but rather adjust the schedule (timings) to give the project the best chance at success. Whereas ‘resource smoothing’ is used when time is limited but resources are available – which means that the project manager cannot locate any extra time to the project but is in a position to allocate additional resources to the project to give it the best chance at success.

2) ‘Resource levelling’ could mean that current resources are shuffled so that there is an increase of resources for the earlier tasks in the project (bringing the workload forward) in order to reduce peaks in the future – however this would have cost and possibly quality implications. However, ‘resource smoothing’ may increase the number of people on project tasks, or have the same number of people working longer hours or add more equipment and then the PM would work to get a smooth ‘usage’ of resources, avoiding troughs and peaks of resource demand and optimising their flow from one task to another.

3) ‘Resource levelling’ includes rearranging non critical tasks in the schedule to reduce demand at peak times when resources may be at max capacity. The PM would aim to use non critical free/total float to optimise the schedule in favour of completing the project within it’s given resource allocation vs ‘resource smoothing’ which would be where the PM adds resources to critical path activities (not to non-critical tasks as this would just add to the free/total float time and not optimise project work) to ensure that the project can be completed within it’s given time constraints.