How to Reduce the Impact of Cognitive Biases on Project Decisions

Grace Windsor
By | Updated March 13, 2017 | 5 min read

Have you ever taken your friends to your favorite restaurant only to be surprised that they didn’t like it? Maybe you recently changed your car and now it seems everyone is driving the same model! Did you ever want to leave a bad movie early but stuck it out as the ticket was expensive and you wanted to get something in return?


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Well, I have experienced all of these situations, and I am sure you have too.

These scenarios are classic examples of cognitive biases, mental shortcuts that influence how we perceive the world, interact with others, and make decisions.

As project management is so reliant upon effective decision-making, understanding the impact of cognitive biases and how we can overcome these limitations is an extremely useful tool for project managers and teams.


The role of Cognitive Biases

Whilst there are numerous examples of cognitive biases, it is useful to understand why we rely on these flawed systems in the first place. The purpose of a bias or mental shortcut is to save mental time and energy when making a decision. Cognitive biases address four key issues:

  1. Too much information: We generate over 5 quintillion bytes of data daily, meaning 90% of the data in the world today has been created in the last two years alone. Consequently, as we need a quick, simple way to find what is useful, we tend to filter and skim through information.
  2. Not enough meaning: We only experience a small part of the world and tend to fill in the gaps with stories and stereotypes.
  3. Need to act fast: The pressure to make quick decisions often leads to overconfidence. We jump to conclusions, focus on the short-term, choose less risky options, and prefer simple options even if they are not the best solution.
  4. What should we remember: This is related to problems 2 and 3. Our memories are flawed as we ‘edit’ and store memories differently than how they were experienced.


Cognitive biases are tools for dealing with these four challenges. Although we may view ourselves as rational individuals in control of our thoughts, actions,  and decisions, we are all prone to cognitive biases of some kind. These errors inhibit our ability to make sound professional and personal decisions. Once we have acknowledged the existence of such biases, we can take action to limit their impact. Below are key individual and team biases encountered during projects with suggestions to counteract these mental shortcuts.


Individual Cognitive Biases


Cognitive Bias (4)


Project Cognitive Biases

In addition to individual biases, there are several biases you should check for when planning and executing a project:

  • Planning Fallacy: Underestimating how long it will take to complete a task
    • Use project history and previous examples to gauge the timeframe more accurately. You could also add some extra time to estimates provided by the team to offset this habit.
  • False Consensus Effect: We often overestimate the extent to which others share our beliefs or opinions, and assume everyone is invested in the project.
    • Actively secure and nurture buy-in from the team and stakeholders when planning and executing the project. Use meetings, workshops, and a collaborative project site to report on project progress and celebrate success!
  • Optimism bias: Project teams become overly focused on optimistic outcomes,  which impacts risk management, project selection, and change management processes.
    • Use project meetings and reports to track the progress against the agreed plan and take actions where needed. Work closely with the appointed change manager or develop a change management plan to aid the implementation of the final deliverable in your organization.
  • Déformation Professionnelle: Viewing a situation in the context of one’s own profession or expertise.
    • During the planning phase, get input from different team members and departments to develop a balanced schedule.


Team Biases

Cognitive biases limit individual decision making and also prevent teams from working productively as a group. Cognitive biases underpin failed projects such as the Airbus 380, the Mars Climate Orbiter, Microsoft Xbox 360, and the proposed NHS Care Records Service.

When managing a collaborative project, keep an eye out for these biases when teams come together.

  • Groupthink: Team members privilege harmony and consensus over critical, rational evaluation of data and facts.
    • Appoint an individual to the role of ‘devil’s advocate. This person needs to question assumptions and plans, challenging the views of the group.
  • Sharedness Bias: Groups rely on information shared by team members, neglecting unshared information from other sources.
    • Use brainstorms and discussions to generate new ideas and inputs from all team members.
  • Preference Bias: Groups often stick to their initial opinions and solutions, and typically shape their analysis of information to support this initial preference.
    • Build diverse teams with different experiences, perspectives, and modes of working to avoid this trap.


When making a team-based decision, it is sometimes useful to defer the final decision for a few hours or days after the initial discussion. The extra time allows the team to reflect on all options and gather more information instead of rushing down the wrong path due to the above biases.



Cognitive biases can wreak havoc on projects, leading to missed deadlines, budget overruns, and failure to deliver. The first step in counteracting cognitive biases is to understand key individual, project, and team biases. Each bias has a particular root cause, function, and remedy. These include using solid data, allowing time to make decisions, and gathering diverse inputs.


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Grace Windsor
Grace Windsor

Grace is a content creator within the marketing team at BrightWork. She loves creating actionable content in different formats to help others achieve more project success. Grace spent far too long at university studying English literature, which instilled a life-long love of learning and upskilling. In her free time, she enjoys a challenging session at the gym, tucking into a good book, and walking the beautiful Galway coastline with her dog.

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