The triple constraint in project management: time, cost, and scope

Project Management Concepts

Question 1; the Triple Constraint

The term triple constraint refers to three interdependent factors which will act as constraints on the way projects are completed. The triple constraints, which may also be called the 'project triangle', will be found in all projects, they are the factors of time, cost, and scope. Successful projects are usually defined as those which are delivered at the right time, within the correct budget, and to the specified scope. These different influences converge, to understand their interrelationship each factor may be considered individually, followed by a discussion on the way in which the influence each other.

The time constraint refers to the timescale in which the project should be delivered, meeting the required completion schedule. For a project to be delivered on time it is essential there is effective time management exercised within the projects, ensuring that each stage of the project is completed on time, to facilitate timely progression. Project managers will utilize project planning models, which may include software, which facilitate the planning of the project, including the development of work breakdown schedules, which identify the different tasks need to be undertaken, and the prerequisites, which can be used to create an effective plan. The project manager will need to assess project progress to ensure that different stages are completed on time, and if the project falls behind them they need to be a reassessment of the schedule in order to bring the project back on track.

The cost is the monetary cost, and relates to the project budget. A successful project will be completed within budget, rather than exceeding that budget. Good planning for projects will usually include a contingency fund in case there are any unexpected items. While the emphasis in terms of financial cost usually refers to achieving the project within budget, it should also be noted that where there is a significant under-spend, there should also be investigated to ensure that there was compliance with the relevant quality requirements.

The dimension of scope refers to the end of the project, and what it is meant to provide. Successful projects will start out with a clear and concise project definition, including what it should be what it should provide, a process that is important in order to minimize the potential for changing boundaries as the project progresses. Therefore, it may also be necessary to define what the project will not incorporate.

There is an inherent interdependency between these factors. For example, the broader the scope of the project, the greater the potential cost and time to complete the project. Likewise, if there is a need to cut the budget, this may reduce the scope of the project. If a project is required quickly, or force behind schedule, in order for the project to be delivered on time it may be necessary to use more resources, for example bringing more labor, which in turn will increase the costs. Alternatively, if the lagging project is still required on time, but there is no more money, the scope of the project may be reduced. Where one of these constraint is impacted directly or indirectly, it will invariably influence other constraints.

Question 2; Systems Approach

The concept of the systems approach views the organization as a system. Systems are made up of internal dependent parts or processes, and assisting may be either closed or open. A close system is completely interdependent and does not interact with its environment and is not impacted by that environment, whereas an open system will interact with the external environment through the presence of inputs, throughputs, and its' outputs. A good example of an open system is an animal; it is a living creature which interacts with its environment through inputs, which may include food and oxygen, which are then digested internally in order to provide energy, and creates outputs, such as CO2 from breathing, and bodily waste, which go back into the environment. A car is an example of a mechanical system, reliant on the acquisition of fuel, and the skills of a driver to operate, and provides an output service, as well as emissions.

The analogy of an open system can be applied to an organization, as the organization will be made up of a number of internal dependent parts and processes which operate together, and will also be reliant on inputs, throughputs which may also be considered transformational processes, and outputs. The application of open systems theory to organizations will usually accepted that the boundaries of the organization are more flexible and ambiguous compared to some other types of system, and that some components within the system, for example the people, may be part of multiple systems.

Applying a systems approach towards the commercial environment allows observers to see organizations as part of a more complex environment, considering the way in which different input influences, such as raw materials, labor, legislation, the competitive environment, and even geographical factors may influence the organizations' choices and performance, as well as the way in which throughputs are managed, and outputs manifest. The process is not simply one of observation, but can also be used in a more proactive manner to determine how certain changes may have impacts, and how the organization may even manage influences, or react to those influences, in order to manage their position.

Question 4; Dependencies in Projects

In a project there is a need to identify dependencies between the different tasks, with some tasks required other elements of the project to be completed before they can progress; for example, one cannot test a system before it has been coded, just as one cannot start to build a house before the land has been purchased. There may be many different dependencies within a project, identifying them will aid with panning and the development of the work breakdown schedule and the development of a Gantt chart, which will show the critical path.

There four different types of dependencies; to start, start to start, finish to finish, and start to finish. These indicate the type of relationship that exists between the two tasks. Finish to start means that a preceding task must be finished before the next task can start, for example before a house can be built, the land must be purchasing the purchase finalized. The start to start dependency is where a predecessor must have been started before the next task can be started, for example, is building a road, the excavation needs to start before the road can be tarmac. As the finish to finish dependency requires that the preceding task must be finished before the subsequent task can be finished, using the example of the road the tarmac in the road must be completely finished before the painting of the white lines can be completed. The final dependency is a start to finish, where a preceding task must be started before the subsequent task can be finished, in the case of the road construction example, the excavation of the road must have started before the painting of the white lines can be finished.

In project management there are likely to be a number of interdependent relationships where dependencies may be based on several preceding or succeeding tasks, with the most common type being a finished a start, where one stage must be finished before another stage can start, the least common dependency is the start to finish dependency.

Dependencies may also be categorized as hands off dependencies, which is a finish to start dependency, or resource dependencies where there is a reliance on resources that are being used for previous tasks; they cannot take place until the resources needed are available.

Question 5; Theory of Constraints

The theory of constraints is a general theory developed by Eli Goldratt, which states that any system will be constrained by its weakest component or link. A commonly used phrase quite often associated with this theory is that 'no chain will be stronger than its weakest link'. In the theory of constraints systems will be made up of different components or processes, but not all will be equally as strong or robust, those that are the weakest will constrain the entire process. By understanding the theory of constraints management may be able to identify their weakest links, which may also be considered as bottlenecks, although most vulnerable components, and reduce or eliminate vulnerabilities. The process is cyclic, as once one weakness or vulnerabilities identified and minimized, another part of the system will become the weakest link, which can then be addressed by management. Notably, this is a general theory; set may be applied to a wide range of different disciplines, for example in the commercial environment it may be applied to manufacturing processes, inventory control, accounting systems, and information technology.

Under the theory of constraints there is a five stage process used to improve systems. The first stage is the identification of constraints; these may include identifying a lack resources or access to resources, policies which place limitations on processes, or any other factor that hinders the achievement of goals by the organization. The second stage takes place once the constraints been identified, and is the identification of an optimum way for the exploitation of any constraints. This may include an examination of the maximum return of capacity that could be gained if the constrained process is influenced and adapted. It may not be financially or practically viable to deal with all constraints, as there may not be a positive cost benefit analysis. The third stage is the subordination of the processes, in which the system or process that is a constraining factor is aligned. This is a stage which is preparing for the fourth stage, referred to as elevation. It is during the fourth stage implementation will take place, with the changes introduced to minimize a constraint. The final stages a review stage, where there is an assessment to identify the results of the implementation, and assess whether or not there is further adjustment needed. This also leads back into the first stage, creating a cycle, where there is a reassessment of the constraints that are present.

Within any process there will be a critical chain, as critical chain is the order of processes or stages which are required to be undertaken for the completion of its output, where any delays will impact on the final completion time. The critical chain is therefore the minimum amount of time it is required for the completion of the project. Critical chain scheduling identifies a critical chain, and schedules the project so it can be completed in the most effective manner, taking into account the different dependencies exist.