Human behaviors in scheduling

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The idea behind this article is to provide the reader with knowledge about the effects of human behaviors in scheduling. The term "behaviors in scheduling" is a broad term that can be seen as how humans act and react to different situations within a project. Scheduling comprises plans and milestones in regard to projects and is often seen in context with distributing resources. There are several ways of behaving in scheduling, and these ways are all affected by how the respective industry and project is assembled. When creating a schedule in a project, there is certain aspects that is similar regardless of the industry and type of project. The majority of schedules are created with the ambition of improving the management of time during a project, optimizing the use of resources, and reducing unnecessary risks. In order to implement this concept on a day-to-day basis for any company, it is vital to have proper knowledge regarding the effects of a functioning scheduling system. In Project Management the behavior could be different than expected, as a result of misinterpretation of a certain situation. It is important for a company to have a safety net that identifies these situations and make sure that a wrong response do not go unnoticed for the rest of the company. This responsibility is often placed on the project manager and his inner circle. As it is difficult to understand what the best behaviors in scheduling are, it is important to have an understanding about how different scheduling methods works. This leads to an increased knowledge about human behaviors when scheduling, which has great value for the project manager, the customer and stakeholders, as well as the company itself [1].

Scheduling methods

In many cases the human behavior is neglected when looking at the effects of scheduling. A company may have great effects from the way they organize and schedules without focusing on the human role in scheduling. This could lead to a point of stagnation regarding the efficiency within the daily activities of a company. The human influence within scheduling consists mainly of relations to other humans and communicating, but it also consists of reacting and acting according to the determined methods of scheduling. What is common for several scheduling methodologies is that they do not emphasize the effect of the human factor within a project. This paragraph presents various methods of scheduling with focus on time management and distribution of human resources in regard to activities related to projects.


A Gannt chart is a common way of visualizing a project schedule and is named from the inventor of the chart, Henry Gannt. The main feature of a Gannt chart is to visualize the project schedule of a project and highlight the tasks related to the project. To make the chart easy to understand, it is common to put as many tasks related to the project as possible in the chart and align these tasks to different deadlines or milestones. It is also common to align the people responsible for each task. As the project progresses, the chart will adjust according to how far the tasks have come, as well as how far the workers related to the tasks have come. These features make the Gannt chart useful for the people involved in the project, as well as the customers and stakeholders. In case of unforeseen events, the Gannt chart is easy to modify. This method is dependent of an understanding of human relationships in a project, as well as certain demands to the type of project. If the project is too large or widespread, then it would not be advantageous to use a Gannt chart for scheduling as it is more likely that this makes it more confusing and therefore against its purpose.


Critical Path Method, CPM, is a method used to estimate the minimum duration of a project, as well as the flexibility of the schedule. This method is considering the amount of time that an activity can be delayed without affecting the start date of a following activity. The critical path is the sequence of activities that represents the longest path through a project. This determines the shortest possible duration of a project [2].


Program Evaluation and Preview Technique, PERT, is a method to visualize and monitor activities related to a project’s schedule. Similar to the CPM, the PERT also uses information such as start dates and finish dates as well as potential delays related to activities. In order for this method to be as efficient as possible, it is necessary to know every task and the potential dependencies between these tasks. CPM and PERT are bot mathematical methods and similar in many ways. A significant difference is that PERT is accounting for time variance, while CPM is working with time estimates[3].


Critical Chain Project Management, CCPM, is a scheduling method that highlights the importance of human resources and other resources required to finish a task. The method is resource dependent, which means that a task cannot be started unless the previous is finished. CCPM is a simple method that establishes the critical chain after considering resource limitations. What is unique with the CCPM method is that it uses a probability activity of 50% when estimating the duration of a project and a project buffer when delivering the project [4]. The method is based on Parkinson’s law, where workers find small irrelevant tasks to fill the time in the task schedule. This is because the importance of finishing a project within the deadline is emphasized in a company, but early delivery is not rewarded. As the CCPM method is simple and does not require any new software, can the plans be created quickly after the resource estimates and activity schedules are available. The CCPM creates a critical chain, while the PERT and CPM create a critical path. The critical chain is the centre of interest for the project manager and is unchanged during the span of a project.

Unforeseen events in scheduling

As a project’s duration often is very long, it is realistic to assume that the project environment will be subjected to unforeseen events. Such events could be changes that affect other activities, a wrong assumption done in the earlier stages of the scheduling or internal conflicts. What is common for these events is that the scheduling methods is not primarily created to handle such unforeseen events. The human approach to these events, and changes in general, is critical in order for a company to circumvent the worst result possible from these unforeseen events.

In Alcoa, an American aluminum company, the new chief executive in year 1987 chose to focus on reporting every minor injury as a result of many injuries to the workers every year. As a result of this, the communication within the company increased dramatically and the injuries decreased at a similar rate[5]. The effect of the organizational structure and culture is often neglected when looking at the scheduling methods but is one of the most important environmental factors that influences the Plan Schedule Management processes [6]. As unforeseen events could occur without any signs, communication within an organization could dramatically reduce the risks of the most critical scenarios.

According to the Oxford English Dictionary, communication is determined as “The imparting or exchanging of information by speaking, writing, or using some other medium”. Based on this, it is clear that there are several ways of communicating, also within a company or a project. As with Alcoa, the company environment is relying on a habit of communication between co-workers and different departments. By sharing their own personal secrets internally with people and departments, they also could benefit from learning from each other.

As habits have been implemented in the lives of humans during many years, the reaction from each human is unique when facing changes. To cope with these unique reactions from each human, change management has been introduced to organizations subjected to changes. Change management is a way of preparing and teaching individuals to adopt with the changes that could occur during the lifetime of a project.

According to Everett M. Rogers, adoption of new ideas and behaviors is a process that does not happen simultaneously for people in a similar environment. In “Diffusion of innovations” the human is divided into five adopter categories when facing changes. Which category the individual is placed in is dependent on the personal characteristic of each individual, as well as the awareness in regard to the changes that occurs.

The five adopter categories are Innovators, Early Adopters, Early Majority, Late Majority and Laggards [7].

Figure 1: Adoption categories [8]

The Innovators are often the risk takers in the society, and do not need much convincing when they see a chance to do something that has not been done before. The Early Adopters are leaders of certain opinions, and they are comfortable with adopting changes and lead through these changes. Once the Early Adopters starts presenting a proposed solution to the change, the Early Majority starts following. The Early Majority often needs some convincing in terms of evidence or stories, but they adapt earlier than the average person. The Late Majority will not adapt unless it has been tried by the majority of people. Together with the Early Majority, the Late Majority is the largest category. The Laggards are the conservative part in the society, and they are the most difficult group to convince. The Laggards usually need statistics and evidence of a successful effect to be convinced. Adaption to a change in a project is dependent on all of these categories as a project consists of many different people. This puts additional responsibility on the project manager because of the understanding of the different types of people in a project environment and what motivates them. The founder of Prosci, Jeff Hiatt, created a change model, the ADKAR model, to help individuals to change. This name of the model, ADKAR, is an acronym for Awareness, Desire, Knowledge, Ability and Reinforcement. By this, the model is focusing on the awareness of the need for change, the desire to support the change, the knowledge of how to change, the ability to demonstrate behaviors, and the reinforcement to make the change last for a long time [9]. The model is helpful for everyone in a project, from the employees to the leaders, and is created to make the introduction of permanent changes as easy as possible.

The effects of human behavior

As human behaviors not always seems to be the highlight in a scheduling method, it is easy to underestimate the importance of human behaviors in project management. However, it exists many cases where the human behavior functions as the cornerstone in a company or during a project. With Alcoa, the change in human behavior changed the whole company from within. As every safety risk was reported by individuals to their responsible leader, it started a pyramid of communication within the company. The adoption of the increased communication habit was not welcomed the same way by everyone in the company, as expected according to Everett M. Rogers. Several workers and stakeholders in Alcoa belonged to the Laggards category, and they recommended their friends and customers to sell their shares in Alcoa sooner rather than later. The annual net income for Alcoa was five times larger 13 years later. This example proves the value of human behavior within an organization. A common phenomenon for humans is to delay a task until it is barely enough time to complete it within the deadline. This is called the student syndrome. The student syndrome is often the cause of delays in a project, as it is common for the worker to either not make the deadline of the task, or to burn out due to a large amount of work in a short span of time. A cause of variation within a project is the student syndrome, and the CCPM is designed to not rely on such causes.

Figure 2: Student Syndrom in a task [8]

The figure shows how effort of a worker drastically increases as the milestone date approaches. It also shows how the effort increases a bit to start with and then experiences a slight dip in effort before rising continuously. This often the case for workers who works harder in the start in order to achieve safety, and then relaxes and waste the safety that they earned early in the activity. The critical chain project managers are aware that an activity may be delayed due to the worker not making the deadline, but they demand the worker to work with only one activity at the time and that the worker started and ended the activity as soon as possible due to resource distribution in the project. It is expected that half of the activities surpasses the proposed deadline. An American company, Harris, benefited from the use of CCPM when building a new wafer plant in year 1999. The size of the new wafer plant exceeded the previous with two inches and the investment was in the range of $250 million. At that time, the expected time to build the plant and make it run at 90% capacity was 46 months. From the use of CCPM, the plant was finished and running at 90% of maximum capacity in 13 months [10].

The human is a vital resource in an organization. When scheduling, the factor of human behavior is not necessarily presented properly and may therefore be neglected by persons not aware of the importance of the correct human behavior. Even though the project manager is responsible for teaching and convey the desired human behavior within a project, there is also responsibility to everyone in an organization to have the correct habits in regards of being able to obtain information and adapt to changes. The ability to openly communicate and share knowledge within a company and between different departments will over time create habits that could form a new successful culture, as well as reducing both economic and safety risks.

Annotated Bibliography

Project Management: A guide to the Project Management Body of Knowledge (PMBOK guide). (2013), Project Management Institute. A handbook of Project Management that gives general but thorough insight topics related to project management. The book consists of many topics for further discussion.

Rogers, Everett M. (1983). Diffusion of innovations (3rd ed.). New York: Free Press of Glencoe. A book that primarily focuses on the Critical Chain Method. Provides a deep understanding about this method for anyone who is related to project management, but also gives insight in why human behave the way they do.

Duhigg, Charles, author. The Power of Habit : Why We Do What We Do in Life and Business. New York :Random House Trade Paperbacks, 2014. A book that debates the science behind the things that we do and the habits that we have. Also discusses how to change bad habits that people or organizations possesses.


  1. Project Management: A guide to the Project Management Body of Knowledge (PMBOK guide). (2013), Project Management Institute.
  2. Project Management: A guide to the Project Management Body of Knowledge (PMBOK guide). (2013), Project Management Institute.
  3. Smartsheet. The Ultimate Guide to the Critical Path Method. Retrieved February 23, 2019
  4. Rogers, Everett M. (1983). Diffusion of innovations (3rd ed.). New York: Free Press of Glencoe.
  5. Duhigg, Charles, author. The Power of Habit : Why We Do What We Do in Life and Business. New York :Random House Trade Paperbacks, 2014.
  6. Project Management: A guide to the Project Management Body of Knowledge (PMBOK guide). (2013), Project Management Institute.
  7. Rogers, Everett M. (1983). Diffusion of innovations (3rd ed.). New York: Free Press of Glencoe.
  8. 8.0 8.1 Rogers, Everett M. (1983). Diffusion of innovations (3rd ed.). New York: Free Press of Glencoe.
  9. What is the ADKAR Model?
  10. Leach, L. P. (1999). Critical chain project management improves project performance. Project Management Journal, 30(2), 39–51.
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