Mistake vs. Error: What’s the Difference, and Does It Matter?
In everyday use, “mistake” and “error” usually mean the same thing: an action, judgment, or result that turns out to be wrong. Some fields use more specific definitions. Neither word, by itself, tells us why something happened or who should be blamed.
That last point matters for leaders. Calling something an “error” might sound more neutral, but people will judge whether it is safe to speak up by what you do next.
Dictionary Definitions of Mistake and Error
Some people argue:
- A mistake implies personal fault.
- An error sounds neutral or systemic.
I disagree.
Dictionary.com defines an error as:
“a deviation from accuracy or correctness; a MISTAKE, as in action or speech.”
It also defines a mistake as:
“an ERROR in action, calculation, opinion, or judgment caused by poor reasoning, carelessness, insufficient knowledge, etc.”
These definitions overlap. A team can agree on more precise terms for its work, but I would not assume that “mistake” means personal fault while “error” means a system problem. We still need to investigate what happened.
A shared vocabulary can help. It becomes a distraction when we spend more time choosing a label than preventing a recurrence.
The Blame Game: Mistakes vs. Errors
Some people say that saying “mistake” is inherently a more blame-based term than “error.” They argue that “mistake” implies personal fault, while “error” suggests a more neutral, technical fault.
I disagree. Again, I think the words are synonyms, a view shared by Prof. John Grout, an expert on mistakes and mistake-proofing (and one of my instructors), as we discussed in this episode of my Lean podcast and an episode of “My Favorite Mistake.”
This distinction often leads to debates over semantics rather than focusing on the real issue: how we respond to and learn from these events.
As I wrote about in The Mistakes That Make Us, what truly matters is how we handle mistakes, errors, or incidents — not the label we attach to them. No matter what we call them, our goal should be to foster and cultivate a culture where people feel safe to admit and learn from them. As I wrote, all mistakes are unintentional by definition:
“Mistakes are actions or judgments that turn out to be misguided or wrong. We believe we are making the right decision at the time but eventually discover it was wrong, whether seconds or years later.”
Does calling it an “error” reduce blame?
Some leaders intentionally use “error” because it feels less personal. If that helps people discuss a problem, fine. But simply changing vocabulary does not create psychological safety. People notice whether the person reporting a problem gets thanked, questioned with curiosity, or punished.
Consider a hypothetical example: someone sends a report using the wrong version of a spreadsheet. Calling it an error instead of a mistake does not tell us whether the files were clearly labeled, how the handoff worked, or whether a check could have caught it. “Be more careful” does not resolve any of those questions.
What to ask after a mistake or error
Start by addressing any immediate harm. Then ask: What happened? What information did the person have at the time? What made the action seem reasonable? What could help us prevent or detect this next time?
Learning does not eliminate accountability. We can expect people to report problems, help understand them, and follow through on improvements. We also need to distinguish an unintended mistake from a deliberate decision to disregard a rule. The label alone cannot make that judgment.
I explore that distinction further in what mistakes are and why we make them. And calling a mistake “stupid” can discourage the very conversation we need to have.
The Power of Language: Incidents and Accidents
The late Paul O'Neill, the former CEO of Alcoa and U.S. Treasury Secretary, thought words mattered greatly in working collaboratively toward Zero Harm. As quoted in this book of collected speech transcripts, O'Neill said:
“It was necessary to change the language. Still, at a lot of places, people talk about accidents. If you think about it, the phrase that goes with accidents is, “We couldn't help it. God must have intended us to be hurt. Nobody wanted it. Nobody planned it. Nobody intended it but we have accidents.”
I said, “No, no. We're not going to have any accidents at Alcoa. We're going to have incidents.” The word “incidents” gives you intellectual permission to figure out what went wrong. How can we make sure it never happens again anywhere?”
Most importantly, O'Neill was leading the culture change — to make it safe for people to speak up about risks and injuries in the name of solving the underlying root causes instead of blaming or punishing people.
Make speaking up useful, as well as safe
O'Neill's example does not mean words are irrelevant. He connected the language to a different way of managing. That is the part worth practicing.
When somebody reports a mistake, thank them for telling you. Ask questions before deciding what caused it. Involve the people who do the work in testing an improvement, and tell them what happened afterward. A respectful response helps people speak up again; follow-through gives them a reason to bother.
Leaders can also describe a mistake of their own and what they changed as a result. The point is not to celebrate preventable harm. It is to make an honest conversation about prevention possible.
Frequently Asked Questions: Mistake vs Error
What is the difference between a mistake and an error?
In everyday use, the words overlap and often function as synonyms. A technical field or organization may define them differently, so check the context. Neither term automatically establishes blame or explains the cause.
Is a mistake always someone's fault?
No. A mistake is typically an unintentional action or judgment that turns out to be wrong. In healthy organizations, mistakes are viewed as opportunities to improve systems rather than blame individuals.
Why does language matter in leadership?
Words influence culture. If leaders treat mistakes as moral failures, people hide them. If leaders treat mistakes as learning opportunities, people speak up — which leads to improvement and innovation.
Learn more about mistake-proofing
I discuss the language and these dynamics, and more, in my online Mistake-Proofing course that's hosted at TKMG Academy.
Here's my blog post introducing the course about it:
You can buy the course individually at TKMGAcademy.com and check current pricing and options for teams (for more information, email info@tkmgacademy.com).
The course is also part of the wonderful collection of courses in the all-access annual subscription.
Explore learning from mistakes before you buy
The Mistakes That Make Us: Cultivating a Culture of Learning and Innovation explores how people and organizations respond when things go wrong. Read a free preview to see how the book approaches learning, accountability, and improvement before deciding whether it is right for you.
I really enjoyed this post. I’ve found it can be really hard to “change the language” at large organizations but agree using words and terms precisely can help us avoid miscommunication and confusion. Regarding mistakes vs. errors, it reminds me of a Decision Analysis course I took in grad school. The professor believed that a “good decision” could still have a “poor outcome” but that doesn’t mean we should label the decision “bad” if it was made in good faith, with the best possible info and data available at the time, etc. I’m curious what your thoughts are on that. Is an action that produces a negative result automatically a “mistake”?
Thanks, Doug, for reading and commenting.
I also go by this definition of “mistake” and use it in my book, “The Mistakes That Make Us”:
“Mistakes are “actions or judgments that turn out to be misguided or wrong.” We believe we are making the right decision at the time but eventually discover it was wrong, whether seconds or years later.”
We can really only judge a decision based on the outcome. If the outcome is worse than expected, it’s fair to call it a mistake.
Now, there’s nuance where we might make the “right” decision that would have otherwise been OK, but some outside circumstances led to a bad result. The mistake might be not anticipating the other circumstances — but that’s not always possible.
There are times, also, when the “wrong” decision might lead to a good outcome. That could be a “happy accident” — a decision we might choose to not repeat.
When watching sports, I do hate the “judge the outcome” mentality — when the Seahawks threw the ball near the goalline in the Super Bowl and got intercepted, that decision was labeled a horrible mistake. Had they scored a touchdown, the decision would have been celebrated as “gutsy.”
But back to your question — I’m less concerned about labeling a bad outcome as a “mistake” when that bad outcome doesn’t result in blame and punishment. If the goal is learning and improvement, we can state the bad outcome as a fact, and a mistake, and not worry about that too much. Our worry is more about, “Can we learn from that?” and “What would we do differently next time?”
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