Why do smart people keep repeating the same mistakes?
The power of looking backward to move forward
Think about the last project you finished. Maybe it was a product launch, a major initiative at work, or a personal goal you set at the beginning of the year. The moment it wrapped up probably felt familiar. There might have been a quick sigh of relief, maybe a few high-fives if things went well, or a few quiet frustrations if they didn’t.
And then something predictable happened. Everyone moved on.
The next deadline appeared. The next initiative began. The next meeting filled the calendar. Reflection felt like a luxury when there were already too many things competing for attention.
Most projects end this way. Once the outcome is known, the story feels finished. The energy that went into planning and execution rarely carries over into understanding what actually happened – both the good and the bad.
But when we skip that step, we quietly accept something costly: we will probably repeat many of the same problems again. The reason is simple. Experience alone does not guarantee learning. Without reflection, experience simply becomes repetition.
In behavioral science and project management, there is a simple practice designed to prevent that cycle – the post-mortem. It has a slightly dramatic name but it is one of the most practical learning tools available for both organizations and individuals.
The Step Most Projects Skip
In medicine, a post-mortem examines a body to determine the cause of death. In project management, the concept is far less grim but built on the same principle: examine what happened after an outcome so you can understand the causes behind it.
A project post-mortem is a structured reflection conducted after a project or major goal concludes. Instead of focusing only on the final result, it asks deeper questions about the process:
What worked well?
What slowed things down?
What assumptions proved wrong?
What would we change next time?
The Project Management Institute has long emphasized the importance of capturing “lessons learned” after projects are completed. When organizations systematically document and analyze what happened, they begin to build a body of knowledge that improves future decisions. Without that process, teams rely on memory, intuition, and sometimes sheer luck.
And that is often where problems begin.
Experience alone does not automatically produce wisdom. It only does so when we take the time to extract the lessons hidden inside it.
Why Reflection Rarely Happens
If post-mortems are so useful, why do so few people, teams, and organizations actually do them?
Part of the answer is time. When a project ends, attention quickly shifts to the next priority. The momentum that carried the project forward suddenly evaporates, and everyone feels pressure to move on.
Another reason is memory. Reflection is most useful when details are still fresh, but that window is surprisingly short. After a few weeks, the small moments that shaped the outcome fade into the background. That includes the missed conversations, the incorrect assumptions, and the unexpected breakthroughs.
But perhaps the most important reason is psychological.
Looking back can be uncomfortable. Revisiting mistakes forces us to confront things we would rather forget. In organizations, reflection can also trigger defensiveness if people fear blame or criticism. It can feel easier to simply close the chapter and move on.
Yet research on organizational learning consistently shows that systematically capturing lessons learned improves future performance by helping teams avoid repeated errors and replicate effective practices.
Reflection, in other words, is not wasted time. It is how experience becomes improvement.
The Strange Way Success Can Fool Us
There is another behavioral trap that makes post-mortems even more important. We tend to analyze failure, but we rarely analyze success.
That instinct seems logical at first. If something worked, why spend time dissecting it?
Decision scientist Annie Duke argues that this mindset can quietly mislead us. Outcomes alone are unreliable indicators of good thinking.
A project might succeed because the market happened to cooperate. A deadline might be met because someone quietly worked unsustainable hours. The goal might be achieved even though the planning process was chaotic.
From the outside, everything looks fine, but the process underneath might be fragile.
Duke describes a common cognitive error called resulting. Resulting is when we judge the quality of a decision solely by its outcome rather than by the reasoning that produced it. A well-thought-out decision can still produce a bad result, and a flawed process can occasionally produce a successful one.
Stepping outside the office and personal goals, this becomes especially clear in environments where the stakes are higher. In backcountry skiing, where a small bad decision can mean an avalanche death or serious injury, it’s common practice to debrief the day with a simple question: “Did I make good decisions, or did I get lucky?” That question forces an honest evaluation of the process. A skier might make several poor decisions and still have a safe day. But without reflection, that “success” can reinforce dangerous habits rather than correct them.
Post-mortems help us untangle those two things. They force us to examine how the outcome happened rather than simply celebrating or lamenting the result.
That shift transforms every project – successful or not – into a learning opportunity.
Curiosity Beats Blame
The most effective post-mortems share one important characteristic: they are blameless.
The goal is not to identify who made a mistake. The goal is to understand how the system allowed something to happen.
Instead of asking “Who dropped the ball?” strong teams ask questions like:
What slowed us down?
Which assumptions turned out to be wrong?
Where did communication break down?
What worked better than expected?
These questions often reveal that problems rarely stem from a single dramatic error. More often, they arise from small misalignments that compound over time: an unclear expectation, a missed conversation, a risk that was underestimated early in the process.
When those patterns are surfaced, teams gain something far more valuable than a simple explanation. They gain a roadmap for improvement.
Turning Experience Into Knowledge
At a deeper level, post-mortems do something important psychologically: they transform experience into knowledge.
Project management researchers describe “lessons learned” as a process of mobilizing knowledge across an organization. When insights from completed projects are documented and shared, they become part of a collective memory that improves future performance.
Without that system, we rely heavily on intuition and recollection. With it, we develop a learning engine that becomes more effective over time.
This principle applies with equal strength to both corporate initiatives and personal goals. For example, finishing a marathon, launching a side business, completing a major work project, or building a new habit all contain valuable data about how we think, plan, and act.
But that data only becomes useful if we take the time to examine it.
A Simple Post-Mortem You Can Run Today
You do not need a conference room, a facilitator, or a formal process to benefit from a post-mortem. A simple reflection exercise can reveal insights surprisingly quickly.
Start with a project or goal you have recently completed. It could be something professional – a work initiative or major task – or something personal like a fitness challenge or habit you attempted to build.
First, write down three things that helped the project succeed or move forward. These might include strategies that worked well, habits that kept you on track, or decisions that made progress easier.
Next, identify three obstacles or moments where things slowed down. These could be missed deadlines, unclear expectations, distractions, or unexpected complications.
Then go one step deeper and ask yourself why those challenges happened. Look beyond the surface explanation and examine the underlying causes. Was the goal unrealistic? Was communication unclear? Did you underestimate how long something would take?
Finally, write down one concrete adjustment you would make next time for each lesson you identified.
That final step matters the most. A post-mortem is not simply an exercise in looking backward. Its real value lies in shaping the next attempt.
The Next Step in Learning
Looking backward can dramatically improve how we approach future projects and goals. But behavioral science offers an even more intriguing strategy.
What if you could learn from failure before it happens?
In the next newsletter, we’ll explore a decision-making technique used by psychologists, military planners, and innovative organizations around the world. It was popularized by psychologist Gary Klein and championed by decision scientist Annie Duke.
It’s called a pre-mortem.
And it might be the most powerful way to identify and avoid risks before your next project even begins.
And keep on shifting (forward and back!).
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This Week’s Shift
A weekly reminder to rethink, reflect, and act:
What is one overlooked learning you can take from a recent project?
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Every week in Behavior Shift Weekly, we share ideas grounded in behavioral science and psychology, practical tools to help you think differently, act intentionally, and build the life you actually want.
References
Duke, A. (2018). Thinking in Bets: Making Smarter Decisions When You Don’t Have All the Facts.
Williams, T., Eden, C., Ackermann, F., Howick, S., Bergamini, V., Daley, A., & Gill, K. (2001). The use of project post-mortems. Paper presented at Project Management Institute Annual Seminars & Symposium, Nashville, TN. Newtown Square, PA: Project Management Institute.
Williams, T. (2006). How do organisations learn from projects? Paper presented at PMI® Research Conference: New Directions in Project Management, Montréal, Québec, Canada. Newtown Square, PA: Project Management Institute.