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In our previous article, we discussed that the traditional theories of project management are obsolete. In fact, Koskela and Howell (2002) presented empirical evidence and theoretical explanation to show the flaws in the theoretical base of project management, which can lead to problems in planning, execution, and control. The shortcomings of current project management have created three categories of problems:

  • Traditional project management creates self- inflicted problems that are detrimental to project performance. In small projects, problems can be solved by a manager intuitively but what about big and complex projects?
  • The lack of a well-established theory for educating and training professional project managers makes project management difficult and ineffective, and it could impact the development of management tools.
  • The lack of a well-established theory also causes the inability to deal with problems and deviations from the theory-predicted results or anomalies. It fails in interpreting the causes of these deviations. Actually, a theory has a key role in continual validity testing and, more importantly, giving directions for future developments. The traditional project management is incapable of succeeding in both.

To show that the implicit theory of project management is not valid, we can refer to empirical evidence, acquired information, and observed results, in the use of various project management methods. One of the concerns is about flow conceptualization. Is it reasonable to consider the precedence of activities by connecting them to their immediate successors in a noncyclic network graph as traditional theories suggest?

In fact, many studies and reported observations claim that rework makes up a large part of project cost and time, especially in project design. The effects of revisions, repairs, and reworks should be studied on the whole life cycle of the project, not only in a specific discipline or component separately. Another concern is the lack of value generation in traditional theories. On the other hand, many studies show the need to compile the customer's requirements to have a comprehensive understanding of the primary intentions and restrictions. Now imagine what will happen on a large project with significant uncertainty about the purpose at the beginning of the project. There is a need for interaction to resolve the ambiguity around the objectives, which is not achievable by a noncyclical network. In a nutshell, there are several pieces of empirical evidence proving the flaws of the theory of project management which can be listed as follows:

  • It is impossible to produce a plan and maintain it complete and up to date. Plans and schedules should be dynamic and kept up with the actual progress.
  • Pushing tasks to execution without considering the needed inputs for achieving them will rely on informal management, which is separate from the management of the plan; this can lead to success or failure! Weekly memos should be issued to ensure availability of various inputs and resources to execute the tasks.
  • The underlying theory for controlling relies on the thermostat model, a reactive model that detects deviations after they occur, which cannot clarify the causes of the deviation. A proactive model should be adopted instead.

Acknowledging the importance of valid and effective project management theories, there is a need to abandon traditional theories. As already stated, flaws in current management theories might lead to undesirable issues in planning, execution, and control which are the main three processes that delineate project management. They interact through a closed loop. In the following sections we will discuss shortcomings of planning, execution, and control under traditional theories and introduce Lean construction alternative theories. In Part 1, we talked about the theory of project. The discussion here will continue to tackle the theories of management for planning, execution, and control as Table 1 shows.

Table 1 Summary of Discussion

Planning: Replacing Management-as-Planning with Management-as-Organizing

Traditionally, planning processes have been widely practiced through the Management-as-planning approach. In this approach, orders are channeled from the managerial part (those who do the planning) to the effector part (those who are responsible for executing the work) as the photo below demonstrates. Put simply, there is a defined separation between the roles of planners and executors where planners don’t engage executors in planning and decision making.

Figure 1 Management-as-planning (MAP) Approach

Alternatively, this separation in roles between planners and executors is overcome through the Management-as-organizing approach. In this approach, planning and decision making are achieved through the collaborative efforts of planners and executors. Each sub-unit in the system has the right to plan, act, and sense. This approach is suggesting that the planning decisions shouldn’t be merely made by the managerial part, but rather planners and executors should engage in continuous and thorough discussions. This way, the theoretical knowledge of planners is complemented with the technical expertise of executors, making the planning process more effective.

Figure 2 Management-as-organizing (MAO) Approach

Execution: Replacing Authorization System with Making and Keeping Promises

The underlying theory of execution acts as an interface between the plan and the work. The traditional execution theory advises that the plans and decisions developed by planners should be communicated to the executors, either verbally or written. It is understood as an authorization system where the central authority (planners) performs resource allocation and handles the decisions, then, communicate these to participants in the downstream chain. Instead of giving orders to the executors and presuming understanding of all the requirements from their side, an alternative approach would be to coordinate work through making and keeping promises and commitments under a two-way communication approach. Put simply, it starts with a request that should be followed by a promise, performance, and declaration of completion. Such an approach could be achieved through the last planner system (LPS) which is a Lean production system.

Lean Construction theory was established with the aim of delivering value to the customer. Doing so in not an easy process, as value is hard to define and accomplish. As a response to this need, LPS was developed through bringing together those who do the planning (who also understand the customer’s value) with those who perform the work, in an attempt to remove constraints, avoid waste, and achieve value. In other words, LPS advocates developing the plan with the participants who will perform the work, making reliable promises, and leading the execution of work based on coordination and vigorous negotiations among various project participants (Hamzeh et al., 2012). Various projects and different companies across many countries have implemented LPS systematically; the results have been promising in terms

Control: Replacing Thermostat Model with Proactive Model

Finally, the underlying theory of control relies on the thermostat model that works as follows, in case the measured performance deviates from the standard performance, corrective measures are taken to ensure the standard is reached. This reactive approach implies waiting for the deviation to occur to initiate corrective actions. A better approach would be a proactive one such as the scientific experiment theory of control. It works through making a hypothesis, conducting an experiment, and testing the hypothesis. This implies proactivity through scrutinizing causes of deviations and eliminating such causes, instead of waiting for the deviations to occur. As such, LPS combines proactive constraint removal with identifying causes of failures and making reliable promises, smoothing thereby workflow uncertainties.

These pieces of evidence are strong enough to claim that a significant transformation is needed in the discipline of project management. The new theory should be able to interpret the practice and should be developed on a concurrent basis with it. It should be explicit and refined by scientists and practitioners. Lean thinking and LPS are among the leading change-makers that are positively transforming the construction industry.


Hamzeh, F., Ballard, G., & Tommelein, I. D. (2012). Rethinking Lookahead Planning to Optimize Construction Workflow. Lean Construction Journal.
Hamzeh, F. R., El Samad, G., & Emdanat, S. (2019). Advanced metrics for construction planning. Journal of Construction Engineering and Management, 145(11), 04019063.
Koskela, L. J., & Howell, G. (2002). The underlying theory of project management is obsolete. In Proceedings of the PMI research conference (pp. 293-302). PMI.

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PhD Student, Department of Civil and Environmental Engineering, University of Alberta (U of A), Edmonton, Alberta, Canada.

PhD Student, Department of Civil and Environmental Engineering, University of Alberta (U of A), Edmonton, Alberta, Canada.

Associate Professor, Department of Civil and Environmental Engineering, University of Alberta (U of A), Edmonton, Alberta, Canada.