Inside the Critical Path – tasks within tasks

A construction project is made up of a series of complex interrelated tasks, these are often mini projects in their own right. Typically, the initial project schedule is a first attempt of many to estimate the total time it will take to complete the project. This draft schedule is based on the cumulative time taken to compete each task, put together in a logical sequence that ensures interdependencies are recognised. The duration of external tasks are either estimates provided by the principal contractor or from potential suppliers and are usually budget estimates that will be more rigorously confirmed at time of order. These are based directly on an understanding of market conditions and a composite of specialist knowledge and experience-based assumptions that are built up to cover design, procurement, construction, testing and delivery.  At this stage the possible benefits of collaborating are not reflected in the draft schedule.

Analysis of the first-pass critical path often identifies opportunities for improvement. While there are usually many options and ideas considered at this stage, one method that gives a real insight into the complexity of most construction projects is to drill down into the detail and assumptions that underpin the task durations in a number of construction areas.

If we assume for simplicity that for a given item the value-adding process time is fixed, then everything else apart from transport and component lead time is some form of contingency. Each element within a task usually has its own independent contingency, which usually increases when the demand on that system is high. The way in which tasks interact mean that in the overall project level system there is a significant contingency waste opportunity. The problem is that both the independent and interdependent nature of the system make this task level contingency waste difficult to model and manage.

Risk pooling mathematics, used to calculate health premiums or supply chain stock levels can be used to demonstrate that by pooling the contingency required to deliver an outcome at the required confidence level you require much less contingency than is forced by using individual task-based contingency.

Repeat projects where the level of collaboration between the suppliers increases with each iteration demonstrate the scope of this opportunity. These later projects usually cost less and are completed faster on successive iterations to a point where the delivery system is optimised.

The ideal would be to have a project delivery approach that involved pooling the contingency from every task across the project and working collaboratively to ensure that everyone in the project supply and delivery chain trusts that the contingency pool will protect them. The level of project performance would simply depend on the quality, capability and reliability of the pool of suppliers.

At DDK we understand this and work with a team of capable and trusted suppliers and delivery partners. We understand that a construction project is a collaborative endeavour that requires all the stakeholders work together with the aim to deliver the project effectively. Selecting the right contractor with the right tools, equipment, skills and experience is 80% of the right answer – the remaining 20% is down to using an advanced task level coordination by using DDKs Construction Management System together with a collaboration focused delivery team.