90% of all IT projects exceed budget or timeline. Not because of bad developers or inadequate tools – but because of systematic thinking errors built into our brains.
These thinking errors are called Cognitive Biases. And they're sabotaging your projects.
What Are Cognitive Biases?
Definition
COGNITIVE BIAS:
Systematic deviation from rational thinking.
IMPORTANT:
- Not stupidity or ignorance
- Unconscious and automatic
- Evolutionarily useful, harmful in complex situations
- Affects EVERYONE – including you
Why They Exist
EVOLUTIONARY PERSPECTIVE:
Quick decisions were essential for survival.
STONE AGE:
"Is that a predator?" → React quickly = survive
False Positive (flee without reason) = low cost
False Negative (don't flee) = death
TODAY:
"How long will the project take?" → Systematically underestimate
Quick estimate feels right
Consequences come delayed
The 10 Most Dangerous Biases for Projects
1. Planning Fallacy
DEFINITION:
Systematic underestimation of time, costs, and risks.
EXAMPLE:
Estimate: "That will take 2 weeks"
Reality: 6 weeks
WHY IT HAPPENS:
- We plan for best case
- We ignore past experiences
- We underestimate complexity
STATISTICS:
- 90% of projects exceed estimates
- Average overrun: 27%
- For large IT projects: 45%
Countermeasure:
REFERENCE CLASS FORECASTING:
Instead of: "How long will THIS project take?"
Ask: "How long did SIMILAR projects take?"
PROCESS:
1. Identify similar past projects
2. Determine their actual duration
3. Use average as baseline
4. Adjustments only with explicit justification
2. Confirmation Bias
DEFINITION:
We seek information that confirms our opinion.
EXAMPLE:
Team lead believes: "React is the best choice"
→ Only reads positive React articles
→ Ignores problem reports
→ Framework decision is already made
WHY IT HAPPENS:
- Contradiction feels uncomfortable
- Confirmation feels good
- Efficient information processing
Countermeasure:
DEVIL'S ADVOCATE:
Someone on the team MUST bring counter-arguments.
PREMORTEM:
"Imagine the project has failed.
Why did it fail?"
RED TEAM:
Separate team tries to disprove the plan.
3. Sunk Cost Fallacy
DEFINITION:
Holding onto decisions because of already invested resources.
EXAMPLE:
"We've invested 6 months in this approach.
We can't stop now."
→ Another 6 months wasted
WHY IT HAPPENS:
- Losses weigh heavier than gains
- Giving up feels like failure
- Sunk costs feel "real"
THE TRUTH:
The 6 months are gone – no matter what you do.
Only the future counts.
Countermeasure:
ZERO-BASED THINKING:
"If we were starting fresh today –
would we choose this approach?"
No? → Cancel, even if it hurts.
KILL CRITERIA:
Define BEFORE project start:
"At what signals do we abort?"
4. Optimism Bias
DEFINITION:
We overestimate positive and underestimate negative outcomes.
EXAMPLE:
"For US it will work"
(even though 70% of similar projects fail)
WHY IT HAPPENS:
- Overconfidence
- Illusion of control
- Motivation maintenance
Countermeasure:
USE BASE RATES:
"How often does this work for OTHERS?"
EXTERNAL PERSPECTIVE:
"What would an outsider say?"
PESSIMIST ON TEAM:
Someone who systematically identifies risks.
5. Anchoring Effect
DEFINITION:
First information influences all subsequent estimates.
EXAMPLE:
Manager: "This should be doable in 2 weeks, right?"
Developer: "Um... yeah, maybe 3 weeks"
(Without anchor they would have estimated 6 weeks)
WHY IT HAPPENS:
- First number serves as reference point
- Adjustment from this point is too small
- Applies even to completely irrelevant numbers!
Countermeasure:
ESTIMATES BEFORE INFLUENCE:
Everyone estimates FIRST alone, without discussion.
PLANNING POKER:
Everyone shows their estimate simultaneously.
Prevents anchoring through early statements.
NO LEADING QUESTIONS:
Not: "That won't take long, right?"
Instead: "How long will this take?"
6. Availability Heuristic
DEFINITION:
What's easily remembered, we consider likely.
EXAMPLE:
Recently there was a security breach.
→ Security is over-prioritized
→ Other risks are neglected
WHY IT HAPPENS:
- Vivid memories dominate
- Media reports distort perception
- Emotional events stick
Countermeasure:
SYSTEMATIC RISK ANALYSIS:
Not: "What comes to mind?"
Instead: Checklist of all risk categories
DATA NOT FEELING:
"How often has this statistically happened?"
Not: "I remember..."
7. Groupthink
DEFINITION:
Groups make worse decisions due to conformity pressure.
SYMPTOMS:
- Illusion of unanimity
- Self-censorship of concerns
- Direct pressure on dissenters
- Stereotyping of outsiders
EXAMPLE:
In meeting: Silence at "Does anyone have concerns?"
Later individually: "I thought it was risky from the start"
Countermeasure:
PSYCHOLOGICAL SAFETY:
Concerns must be rewarded, not punished.
ANONYMOUS FEEDBACK:
Written before discussion
MANDATORY DEVIL'S ADVOCATE:
Rotating role that MUST disagree
LEADER SPEAKS LAST:
Hierarchy influences opinions
8. Dunning-Kruger Effect
DEFINITION:
Incompetence leads to overestimation of one's own abilities.
EXAMPLE:
Junior dev: "Microservices? Sure, I'll do it in 2 weeks!"
Senior dev: "That's complex. Let me analyze..."
WHY IT HAPPENS:
- To know you can't do something,
you must partly be able to do it
- Beginners don't see the complexity
Countermeasure:
INCLUDE EXPERIENCE:
Seniors estimate, juniors learn
SECOND OPINIONS:
When uncertain, ask external expert
RETROSPECTIVES:
Systematically compare estimates vs. reality
9. IKEA Effect
DEFINITION:
We overvalue things we created ourselves.
EXAMPLE:
"My self-built framework is better than React"
(Objectively: No)
WHY IT HAPPENS:
- Emotional attachment through effort
- Justification of investment
- Pride in own work
Countermeasure:
EXTERNAL EVALUATION:
Someone uninvolved evaluates
BUILD VS. BUY FRAMEWORK:
Objective criteria BEFORE development
REGULAR REVIEWS:
"Would we still build it this way today?"
10. Escalation of Commitment
DEFINITION:
Increased investment in a failing approach.
EXAMPLE:
Project is going poorly
→ "We just need more resources"
→ More people are added
→ Project goes even worse
→ "We need EVEN more resources"
→ ...
WHY IT HAPPENS:
- Sunk cost fallacy
- Avoid losing face
- Hope for turnaround
Countermeasure:
EXTERNAL REVIEWS:
Uninvolved people assess project health
KILL CRITERIA:
Pre-defined cancellation conditions
FRESH TEAM:
New perspective without emotional attachment
Biases in Typical Project Situations
When Estimating
TYPICAL BIASES:
- Planning fallacy
- Anchoring effect
- Optimism bias
COUNTERMEASURES:
1. Independent estimates (Planning Poker)
2. Reference Class Forecasting
3. Plan buffers (20-30%)
4. Validate estimates with seniors
In Technology Decisions
TYPICAL BIASES:
- Confirmation bias
- IKEA effect
- Availability heuristic
COUNTERMEASURES:
1. Objective criteria BEFORE research
2. Devil's advocate
3. Proof of concept with multiple options
4. Get external expertise
In Project Corrections
TYPICAL BIASES:
- Sunk cost fallacy
- Escalation of commitment
- Groupthink
COUNTERMEASURES:
1. Zero-based thinking
2. External project reviews
3. Kill criteria
4. Blameless culture
Team Practices Against Biases
1. Regular Retrospectives
FORMAT:
- What did we estimate vs. what was real?
- Which assumptions were wrong?
- Which biases did we observe?
IMPORTANT:
- Blameless: Mistakes are human
- Systematic: Recognize patterns
- Actionable: Concrete improvements
2. Red Team Reviews
PROCESS:
1. Separate team receives project plan
2. Task: Attack the plan
3. Identify weaknesses
4. Develop countermeasures
WHEN:
- Before major decisions
- For critical projects
- Regularly for long-term projects
3. Anonymous Risk Collection
PROCESS:
1. Everyone writes down risks (anonymous)
2. All risks are collected
3. Joint prioritization
4. Define measures
WHY ANONYMOUS:
- Hierarchy is neutralized
- Honesty increases
- Unpopular opinions are heard
Checklist: Bias Awareness in Projects
BEFORE THE PROJECT:
□ Reference class forecasting done?
□ Kill criteria defined?
□ Estimates gathered independently?
□ Buffers planned?
DURING THE PROJECT:
□ Devil's advocate role filled?
□ Regular external reviews?
□ Retrospectives with bias focus?
□ Anonymous feedback channels?
WHEN PROBLEMS ARISE:
□ Zero-based thinking applied?
□ Sunk costs ignored?
□ External perspective obtained?
□ Kill criteria checked?
Conclusion: Learning to Live with Biases
Cognitive biases don't disappear through knowledge. They're part of our thinking. But we can build systems that compensate for them:
Key Principles:
- Awareness: Knowing biases exist
- Structures: Processes that neutralize biases
- Diversity: Include different perspectives
- Data: Replace gut feeling with evidence
- Feedback: Systematically learn from mistakes
The uncomfortable truth:
You're not rational. I'm not. Nobody is. But teams with good processes can make better decisions than any individual.
Want to understand how to make better decisions as a team? Our guide on Making Decisions shows frameworks like RAPID and Pre-Mortem for structured decision processes.
