Clever project scheduling to arrive on time.
Everyone has that one friend who is always late for everything. I often find myself wanting to quote older relatives at them ‘Failing to plan is planning to be late!’. Maybe they are just disillusioned with scheduling? I don’t blame them. It can make your brain hurt, but there is help at hand!
The project schedule is a key tool in Project Management. It is also usually a key document in forming the project contract. A linear project schedule details the project start date, activity durations, key milestones and end date. It is usually represented as a Gannt Chart and the more of them you see, the more they make sense. However, like any tool, with more input the project schedule can do so much more. Project schedules can be used to allocate resources, materials and costs. They can then be used to provide useful information on baseline cashflows, expected resource histograms and contingency planning (float). Once there is a baseline schedule, this can be used to track progress, measure productivity and estimate the impact of variations. For now though, let’s just stick with the schedule itself.
Planning the Project Schedule
Scheduling varies from being very straightforward to incredibly complex. This depends on the size/difficulty of the project, the interdependence of project elements and the constraints with regards to deadlines and budgets. I have built schedules that range from 20 activities to 4000 activities (avoid at all costs!!!). Fortunately, there are a host of scheduling products which can be used to build your schedule depending on your needs. I am most familiar with Microsoft Project and Asta Powerproject but there are literally thousands to choose from with different levels of functionality and price points. Regardless of how complex your project is, the scheduling process should always follow the same fundamental principles.
Work Breakdown Structure
Start with the Work Breakdown Structure (WBS). It sounds fancy but ultimately this just means breaking the project down into its headline parts. For example, a typical new build might be broken down into;
- groundworks
- utilities and services
- foundations
- framework
- cladding & roof
- external doors and windows
- internal walls
- HVAC
- building finishes
- masonry finishes
- plumbing
- electrical
The WBS allows an overview of the main project works and can then be expanded to detail all the activities required.
Estimate Durations
Once activities are determined, an ‘effort-led’ duration can be established for each. This means that a competent person can estimate the most likely duration of an activity based on available labour. Activity durations are generally predictable through experience, but if there are elements of risk involved (e.g. bad weather) determine best case, worst case and then most likely durations. Contingency periods (or float) can be built in to allow for this risk.
It can also be useful to build in lag time. This simply means an enforced wait time between two activities. For example, there may be a lag of 2 days between completing plastering and commencing decorating to allow plaster to set.
Key Milestones
These are not activities but are points in the project when a certain key achievement or event is due. Once a milestone is achieved or reached, it can trigger other parts of the project to commence. For example, the milestone ‘completion of building framework’ may then allow first fix for several different trades. Milestones may trigger certain payment mechanisms in the contract. They can also act as a strategic overview for stakeholders who are less interested in the detail of project activities.
Dependencies
When all relevant activities and milestones have been determined, it is important to understand how they relate each other or how they might depend on each other. If activity B cannot start until activity A is finished, there will be a start-finish dependency between the two. For example, if cladding cannot commence until the building framework is in place, there is a dependency between these two sets of activities. Alternatively, activities may have no real relation to each other, but both need to be completed. For example, kitchen fitout and bathroom fitout are not reliant on each other and so would have no dependency. Scheduling software allows relationships between activities to be fixed so that the delay of an activity can automatically lead to a reschedule in its successor or dependent activities. Clever!
Critical Path
Once all activities, milestones, durations and dependencies have been input, the critical path of the project can be determined. This is simply all the critical activities which need to be completed on time in order to achieve project completion on time. If an activity on the critical path is in delay, the entire project will be in delay unless mitigated. The critical path shows the longest duration of dependent activities and is often monitored to determine essential project progress. Although there is extensive logic and calculation behind determining the critical path, these days most scheduling software will do it for you. Double clever!
Baseline Schedule
Once a project schedule is agreed it is fixed and becomes the baseline schedule. This is generally key in project contracts because it is the base from which any extensions of time can be agreed. As the project progresses, the schedule should be updated to show actual progress and the impact of any delays or variations. Again, most scheduling software makes this very easy to do by comparing the current schedule with the baseline. (Can I get a ‘Triple clever’?) Do remember however, that the project schedule is a tool. It is only as good as the information you put into it and should be used to guide decision making rather than determine it entirely.
Again, the project schedule can be so much more than a list of interconnected activities. When resources and costs are built in, it can determine your resource requirements, cash flow, earned value, and cost/schedule performance indicators. Head hurt yet? If you (or your late friend) want more information or advice on building the project schedule, just drop us a line. Because failing to plan, is planning to be late.