Developed by Alexandros Bellos
Brainstorming is a data gathering and creative thinking process widely used in project management, where groups of people, or teams, get together in order to generate ideas and possible solutions about a specific common problem or area of interest. It was not communicated as a formal creative process until Alex Osborn detailed the practice in the book Your creative power in 1948. Currently, as a research-based divergent thinking tool, recommended also in the PMBOK® Guide, brainstorming is considered as one of the dominant idea-generation techniques.  
In almost every project, creative thinking on a daily basis is a vital element for the project success. Therefore, in order to achieve that and reach their team's common goals, project managers often organize brainstorming sessions and have the role of facilitator.
Typically, a brainstorming session is structured in a way that participants share different perspectives, experiences, lessons learned about the problem and their ideas are recorded for later analysis. All the participants need to have a clear understanding of the problem and its context and acknowledge the defined and necessary steps of the process. Moreover, it is imperative that everyone is equal and shares different perspectives.
Group dynamics can be proven crucial for the effectiveness of a brainstorming session. When individuals generate ideas alone, no one disagrees or judges the quality of an idea or its owner. On the contrary, during a brainstorming session, participants are actively engaged in discussion, increasing the amount of generated ideas and possible solutions. Ergo, the key to effective brainstorming is creating an environment that encourages a spectrum of ideation.
In the following article, the origin of brainstorming from the Osborn's method and the term of creative thinking will be analyzed, followed by the key aspects and their constraints, for a successful and effective brainstorming session that project managers need to take into consideration. Finally, various types of brainstorming techniques will be presented, and the importance of the facilitator as a key-role will be explained.
Overview of Brainstorming
Creativity and Creative Thinking
People’s mind generates a concept and afterwards explores the value of that concept. Altough some of these concepts do not originally make sense, after connecting them to possible benefits and establishing logical connections, the result can often be a possible solution to a problem.
Creativity is a total package of attitude, thinking skills, thinking techniques and processes which enlarge the capability to break through the pattern thinking and to establish new connections in someone's brain. It is a very important skill for everyone, including project managers and project team members, when the need for generation of ideas or solutions for different problems and issues arises, not only during extraordinary situations but also in daily life. Although it is ocassionally perceived as an inherited trait, it is in fact a soft skill and can thus be further developed and improved through training.  Creative thinking is the art of breaking with patterns, habits and certainties and the art whereby something new is formed, which is somehow valuable. It can be affected by various factors, such as the current mindset, the techniques used to empower it and the different types of environment. In most of the organizations nowadays, creative thinking provides the basis for any attempts to adapt to change and, therefore, might have crucial effect on the long-term organizational performance. 
Facilitating group creativity
Apart from individual creative thinking, it is important for every project and organization in general, to be able to facilitate group creativity in a way that will maximize the potential benefits. Firstly, both the problem itself and the identified constraints around it should be clear and understood by every group member. Otherwise, the ideation will lack focus. Moreover, not all problem-solving techniques are suitable for every case. For that reason, it is essential that according to the background and dynamics of the group of people that will participate and the circumstances affecting them, the most suitable technique to be chosen. By defining the size of the group and choosing participants with specific background, attributes and interest around the common issue, it is more probable that both the session will be effective and that the facilitator will be able to facilitate group creativity. 
Origin of Brainstorming
Creativity can thrive in an environment where the flow of ideas is encouraged, without criticism, thus, creative thinking is a core element of brainstorming. In 1939, Alex Osborn, an advertising executive and co-founder of Batten, Barton, Durstine & Osborn (BBDO), urged by the ineffectiveness that his working environment encountered during the business meetings at that time, started his research on creative-thinking and creative problem-solving methods. In 1942, his book How to Think Up was published, and the term Think Up was firstly introduced , which was later also mentioned and became widely known as Brainstorming, at his book Your creative power, which was published in 1948. Osborn, among others, suggested to use the brain in order to storm a particular problem. In 1953, his book Applied Imagination: Principles and Procedures of Creative Problem Solving was published, which made the brainstorming technique widely popular .
Osborn’s method was based on the principle that people should free their minds and be encouraged to generate ideas rather than be afraid of being criticized. He described brainstorming as a "conference technique, where a group of people generate ideas, attempting to find solution to a specific problem" and suggested four key rules, that if followed, could result in a great amount of high-quality ideas, and therefore, higher possibility to successfully tackle the problem:
- Refrain from criticism and judgement of ideas, especially before the session is over.
- At the beginning of the session, focus should not be put on the quality, but on the quantity of ideas.
- Radical and innovative ideas should be encouraged and never rejected before further discussion.
- Improvement of existing ideas and possible combination of them should also be encouraged 
Application of Osborn's Brainstorming Technique
Before a brainstorming session is applied, it is very important for the project manager to take into consideration the key rules of Osborn. In that way, participants will be inspired by the creative environment and the effectiveness of the session will be maximized.
The first step of a brainstorming session is the Problem Statement, where the issue is described consicely, including its parameters that should be tackled or improved. The problem statement, together with the most important details around it must be understood by all participants before proceeding to the next phases, since it is the basis and the focus area of the whole session. Moreover, the problem should be realistic, with feasible possible solutions. The Problem Statement phase can be summarized in the following steps:
- Briefing by the owner of the problem, which is summarised in a question focusing on "one concrete single target".
- Making clear who the problem owner is.
- Exploring the "why" and "how" questions.
- Further clarifications and explanation.
- Individual reformulation of the question.
- Definitive question statement.
- Confirmation that the problem is understood and that participants have no further relevant questions.
The second phase of the session is called Divergent phase. During the divergent phase, participants are encouraged to generate as many innovative and radical ideas as possible, by freeing their imagination, without being afraid of judgement and criticism. It is important for everyone taking part in the session to keep in mind that:
- Thinking in old patterns will not assist the generation of more ideas.
- Many ideas mean many opportunities.
- All ideas are considered valuable income and should not be turned down prior to discussion.
- Ideas can derive also from other ideas by building on them further.
- All ideas, statements and thoughts should be recorded so as not to be forgotten.
During the Convergent phase, the facilitator urges the participants to examine thoroughly all the ideas generated at the divergent phase and frame them by taking into account the constraints of the problem. It is important to proceed with a mindset of:
- Keeping the original goal and the problem statement in mind.
- Remembering all the constraints and limitations around the problem.
- Thinking possible opportunities that can derive from each of the mentioned ideas.
- Examining how these ideas can be translated into an action plan.
Results from Brainstorming Session - Decision Making process
The decision-making process follows the brainstorming session and it is equally important. Project managers and/or problem owners, have to consider the outcomes of the brainstorming session and proceed with the selection of the ones that can most effectivelly tackle the problem. This decision will have a big impact not only to the problem itself, but also to the whole project or even the organization. Numerous decision-making tools are available, with the Decision Matrix Analysis and Cost-Benefit Analysis being two of the most commonly used.
Decision Matrix Analysis
Decision Matrix Analysis is a decision-making tool widely used in cases that the problem has several aspects, hence, all of them need to be taken into consideration. However, that requires that various good ideas - possible solutions - have been already generated so as to tackle all these aspects. The application of the Decision Matrix Analysis is presented through the following steps: 
- All the available options that were produced during the brainstorming session are listed as rows on a table, while the different aspects of the problem that need to be tackled are listed as columns.
- All the cells must be filled with a number between zero and five, depending on the level that each option can affect every aspect, where zero means "not at all" and five means "very much".
- A number between zero and five is also assigned to every aspect of the problem, depending on its relevant importance, where zero has the lowest and five has the highest importance.
- By multiplying the number of each cell by the number of the aspect's relevant importance, the results in all cells are the weighted scores.
- The final step is to add all those weighted scores from each column, resulting to the sum of each row. The bigger number translates into the idea/solution with the highest priority.
After applying the Decision Matrix Analysis, the decision maker(s) can prioritize each aspect and its possible solution depending on the weighted scores and create an action plan based on it.
Another decision-making tool which is applied in a variety of problems, is the Cost-Benefit Analysis, developed by Jules Dupuit in the 1840s. The tool examines the relationship between the potential benefits that will result from each solution that was generated and the cost of each one of them. For the successful application of the tool, a specific payback period must be defined. Altough Cost-Benefit Analysis is easy and quick to apply, it should not be compared with other tools that provide complex and critical financial support to decision making process. The application of the Cost-Benefit Analysis can be summarized in the following steps: 
- Firstly, all the costs associated with the solutions and the problem of the project are listed, followed by the listing of the benefits of these solutions.
- Each of the above listed costs are assigned to a monetary value, which includes cost-estimations for all the resources needed.
- The discount factor is calculated [%] and the cost value and cumulative costs are listed and assigned to a monetary value.
- Likewise, a monetary value is assigned to all the benefits that will result from each solution, including possible benefits that may occur during the whole payback period which was defined at the beginning.
- Finally, the benefits and the costs listed above are compared.
If the steps above were completed successfully, the comparison between costs and benefits will provide a clear result which will help the project manager or problem owner to decide whether to proceed with this specific solution or not.
Variations of Brainstorming Techniques
Apart from the Brainstorming Technique that Osborne introduced, nowadays there are many variations of brainstorming, developed and applied to satisfy the needs of various projects and organizations in general.
A common problem of the traditional brainstorming technique is that participants during the session do not know where to start from, either because they can not perceive all the aspects of the problem, or because the problem is so complex that the ideas generation is low. When the time-frame for deciding upon solutions is narrow, affecting the success of the project, the Reverse Brainstorming technique is applied. 
The application of Reverse Brainstorming follows a reverse procedure comparing to the traditional one, starting with facing the problem from a totally different perspective. The question now is not how to solve the problem, but how to make it even worse and complicated . Although at first the problem might not make sense to the participants when viewed through these lenses, it is proven that when they break free from the pressure and fear for criticism, the idea generation increases. After generating numerous ideas about how to make the problem worse, the facilitator asks the participants to reverse these ideas, resulting to surprisingly positive solutions that can possibly solve the problem.
The Nominal Group technique
Nominal group technique is an alternative brainstorming method, most suitable when dealing with more passive participants. The basic advantage of this technique is that it gives equal opportunities to people regarding participation and contribution. People are split into small groups and everyone have the same amount of time to generate ideas about the common problem. Afterwards, the facilitator gathers the ideas and writes them down. The most important step of this brainstorming method is the voting part, where everyone in secret votes for the best, the second best, the worst and -so on- idea. At the end, the results are becoming known to the rest of the participants.
Brainwriting is very similar to brainstorming since both of them are used for the same cause. However, the biggest difference between the two, is the lack of competition each participant feels during the process of brainwriting. This technique allows people to express their ideas without the fear of rejection and criticism, since everyone’s voice can equally be heard. Apart from that, this method, is suitable when dealing with a large group of people and different problems. The basic concept is that in a sort amount of time each person should write down in a piece of paper ideas about a specific problem, which is different from the others. After time passes, the papers are mixed and being redistributed so that everyone has now a different problem than before for which they should brainstorm about. The process continues for as long as the facilitator of the session decides .
Brainstorming is a dominant idea-generation technique and it is applied daily in every industry, project and group. It empowers proactive engagement to discussion between teams and can result to extremely beneficial ideas. However, brainstorming is affected by a variety of limitations. Firstly, by its application, a great amount of ideas can be generated, yet these are not final decisions and courses of actions. It is required that a decision-making tool will be applied as well in order to decide the exact way to tackle the occuring issue.  What is more, brainstorming's success is totally dependent on people, hence the group dynamics can affect the result to a great extent. Choosing the amount of people that will participate in a brainstorming session, checking their background and their relevance to the problem, defining the facilitator and creating an environment where creative thinking can thrive and everyone feels equal and avoid groupthink, are not always achieved, leading to sessions that have no outcomes at all and are simple waste of resources. Another limitation of brainstorming is the fact it is time consuming.  Participants need time to totally comprehend the problem, receive answers to their questions, think out-of-the-box and have a flow of ideas. Therefore, each project manager should wisely decide upon the technique that is most suitable according the circumstances in order to increase the effectiveness and the efficiency of the session.
Osborn, A. (1953) Applied Imagination: Principles and Procedures of Creative Problem-Solving. Applied Imagination: Principles and Procedures of Creative Problem-Solving was written and published by Alex Osborn in 1953. At his book, Osborn introduces the term "brainstorming" , a method which explains and highlights creative thinking, based on the principle that people should free their minds and be encouraged to generate ideas rather than be afraid of being criticized.
Project Management Institute. (2013) A Guide to the Project Management Body of Knowledge (PMBOK® Guide). A Guide to the Project Management Body of Knowledge (PMBOK® Guide) is a collection of knowledge areas and processes recognized as best practice for project managers. It provides the fundamentals of Project, Program and Portfolio Management and defines brainstorming as a technique which is used in order to generate ideas related to project and product requirements. Although decision-making of solutions is not included in the brainstorming process, some of its variations does.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Osborn, A.F. (1953) Applied imagination: Principles and procedures of creative problem solving , NY: Charles Scribner’s Sons, Third Revised Edition.
- ↑ 2.0 2.1 Project Management Institute. (2010) A Guide to the Project Management Body of Knowledge (PMBOK Guide), Project Management Institute. ISBN: 9781930699458, 193069945X
- ↑ Adair, J. (2007) The Art of Creative Thinking: How to Be Innovative and Develop Great Ideas, Kogan Page, p.109-118. ISBN: 9780749447991,0749447990
- ↑ Van Loon, C. , Andersen, H. , Larsen, L. (2017) Facilitation - Create results through involvement, DJØF / Jurist- og Økonomforbundets Forlag. ISBN: 9788757438734
- ↑ Osborn, A.F. (1942) How to Think-Up. McGraw-Hill book Company.
- ↑ 6.0 6.1 Axelrod, A. (2009) RISK: The Decision Matrix: Strategies That Win, Sterling. ISBN 13: 9781402754104
- ↑ 7.0 7.1 Boardman, A. (2010) Cost-Benefit Analysis, Concepts and Practices , The Pearson Series in Economics, Fourth Revised Edition. ISBN 10: 0137002696
- ↑ 8.0 8.1 8.2 Wilson, C. (2013) Brainstorming and Beyond, Morgan Kaufman. ISBN: 9780124071575
- ↑ Yayici E. (2016) Design Thinking Methodology Book, ArtBizTech
- ↑ Islam, R., Abdullah, M. (2011) Managing Quality in Higher Education: Applications of Nominal Group Technique. Directory of Open Access Journals. ISBN-13: 978-3846532539