#583 Anecdotes versus Data: What D-Day Teaches Leaders About Better Decisions
Anecdotes versus Data: What D-Day Teaches Leaders About Better Decisions
What is your decision based on? It is one of the most legitimate questions anyone in an organisation can ask, and one of the least welcome. In the latest episode of The Leadership Podcast, leadership expert Niels Brabandt examines why so many leaders still answer it with seniority rather than substance, and what one of the most consequential weather forecasts in history reveals about the difference between anecdotes and data.
The responses are familiar to anyone who has sat in a leadership meeting. "I have been in this industry for twenty years." "How long have you been here?" "Do you think you could do better?" None of these answers the question. Each of them shifts the conversation from the quality of the decision to the status of the person making it. Niels Brabandt notes that the topic came directly from listeners who wrote to him describing exactly this pattern in their own organisations.
Anecdotes Are a Starting Point, Not a Conclusion
Brabandt is careful not to dismiss anecdotes. Anecdotal evidence exists, and in some fields it is indispensable. Pharmaceutical research is the clearest example. When participants in a supervised trial report dizziness, nausea or no effect at all, those reports are anecdotes. They are also the first signal that something deserves investigation. As Brabandt points out, roughly two in three early anecdotal reports of side effects are later confirmed by rigorous studies, and one in three is not.
That ratio captures the core of his argument. An anecdote is valuable because it tells you where to look. It becomes dangerous when it is treated as the answer. Stopping at the anecdote is comfortable and humanly understandable, but it is rarely the route to a sound decision. Data is the harder way, and it is the better way.
The Forecast That Changed History
The second reason for the episode is the 2026 film Pressure, directed by Anthony Maras, with Andrew Scott as the meteorologist James Stagg and Brendan Fraser as General Dwight D. Eisenhower. It dramatises one of the most consequential decisions of the twentieth century.
In June 1944, the Allied landings in Normandy were scheduled for 5 June. Group Captain James Stagg, a civilian meteorologist given a wartime commission to lead the forecasting for Eisenhower's headquarters, warned that a severe storm would make a landing on that date impossible. His American counterpart, Colonel Irving P. Krick, argued that conditions would be acceptable. Krick relied heavily on historical weather maps: if the current pattern resembled previous years, the outcome would resemble them too. In an era without satellites or modern computing, this was a recognised approach. In this case, it was wrong.
Stagg's warning was grounded in the current data, and the Norwegian meteorologist Sverre Petterssen identified something more: a brief window of acceptable weather between two storms. Eisenhower postponed the operation by twenty-four hours and, in the early hours of 5 June, gave the order to proceed on 6 June. The storm struck on the original date. The landings went ahead in the gap, against an enemy that did not expect anyone to attempt a crossing in such weather, and the Allies established a foothold on every beach.
For Niels Brabandt, the story is not abstract. The success of D-Day opened the way to the liberation of Western Europe. In April 1945, units of the US Third Army, among them Captain Frederic Keffer, reached the Buchenwald concentration camp, where Brabandt's grandfather, a German resistance fighter, was imprisoned. Without a successful D-Day, he notes, he would not be here today.
The Conference Anecdote
Most business decisions are less dramatic, but the pattern is identical. Brabandt describes a scene that many IT and operations leaders will recognise. A senior executive returns from a conference and announces that a competitor now does "everything with AI". Could the organisation please do the same?
A little research usually tells a different story. The competitor has a single prototype, about to be tested in a limited area, with any decision on a wider rollout still to come. That is not "everything with AI". It is a pilot. The anecdote and the data describe two very different realities.
Even well-funded initiatives fail when the evidence is thin. Brabandt cites IBM's Watson effort in cancer care, which was meant to help clinicians identify patterns earlier and was ultimately shut down after it failed to meet clinicians' needs in practice. The lesson is not that ambitious technology projects are a mistake. It is that the decision to pursue them must rest on evidence rather than on what someone heard at a conference.
He also warns against the logic of a sample of one. Someone made money buying a particular share, so you buy it too. Past performance does not predict future returns, and one person's experience is not a data set. Brabandt describes this as a gap in education rather than a flaw of character, and he stresses that sound evidence-based judgement is a skill that can be learned.
Time Sets the Standard for Evidence
Why do capable leaders fall back on anecdotes? Often because of time. There is a fundamental difference between having six months, six weeks, six days, six hours or six minutes to decide. The more time available, the higher the standard of evidence that can, and should, be expected.
Eisenhower did not have the luxury of commissioning further studies. The tides and moonlight required for the landings would not align again for roughly two weeks, and more than 150,000 troops were to cross the Channel on the first day alone. He decided with the best data available in the time available. That is the standard Niels Brabandt sets for leaders: the quality of a decision depends on the anecdotes at hand, the research data that can be gathered and the time the situation allows.
Accountability Cannot Be Delegated
The final part of the episode turns from evidence to ownership. Eisenhower prepared two statements before D-Day: one for success and one for failure. The second, written in case the landings were repulsed, ended with a sentence that has become a reference point in leadership: "If any blame or fault attaches to the attempt it is mine alone."
Brabandt contrasts this with a pattern he sees in many organisations: leaders who expect to be celebrated when things go well and point at a team leader, a data supplier or a process owner when they do not. That, he argues, is not leadership. The choice and its consequences sit with the leader. It is the reason for the leadership role, and for the leadership pay grade that comes with it.
A Practical Framework for Decision-Makers
Start with the anecdote. Treat it as a signal that shows you where to look, never as the conclusion.
Ask for the evidence. Who said it, on what basis, and what does the underlying data actually show?
Match the evidence to the time available. With six months, demand rigour. With six hours, decide on the best data you have and be transparent about its limits.
Decide and own it. Seek excellent advice, then take full responsibility for the outcome, whatever it turns out to be.
Sustainable Decisions
Anecdotes are not the enemy of good leadership. Unexamined anecdotes are. Leaders who use anecdotes to find the data, weigh both against the time they have and then stand by their decision make choices that work not only in the short term but in the long run. In the words of Niels Brabandt, that is what makes a decision sustainably great.
The full episode of The Leadership Podcast with Niels Brabandt is available as a videocast on YouTube and as a podcast on Apple Podcasts and Spotify.
Niels Brabandt
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More on this topic in this week's videocast and podcast with Niels Brabandt: Videocast / Apple Podcasts / Spotify
For the videocast’s and podcast’s transcript, read below this article.
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Contact: Niels Brabandt on LinkedIn - https://www.linkedin.com/in/nielsbrabandt
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Podcast and Videocast Transcript
Niels Brabandt EMBA MBA MSc
What's your decision based on? And of course you can now say, "Look, you're not questioning my decisions." When I make decisions, I say you obey. Of course, freedom of speech: you can say that, which is not the most modern approach to leadership, and actually not a scientifically sound one. However, you are able to say that. Let's face it, most people don't do that anymore because they realize quickly, "That's not going to work out in the future at all." However, when you then look at the answers some people give, when you say, "What is your decision based on?" you receive answers such as, "Oh, I am 20 years in the industry, it's my experience." Or they give you a counter question such as, "How long are you in the industry? Why do you dare questioning me? Do you think you can do this better?" And suddenly we are in exactly the situation that people send me via email, that they sometimes wonder if people are aware of how they should make decisions.
Niels Brabandt EMBA MBA MSc
The question is, "What are your decisions based on?" And that's exactly the topic we are going to talk about today, because we need to talk about, "Do you actually allow your decisions to be based on either data or based on anecdotes?" And by the way, just to get this up front, anecdotes are not automatically bad. However, there is a key aspect of anecdotes which makes it more difficult to allow this to be the foundation for your decisions. Let's face the situation here. Okay, anecdotes. And by the way, the reason why we have this episode right now is, of course, a specific one. First, I received emails about this, and when I received questions - so thank you very much for contacting me - I always look at which topic comes up the most, and which is most relevant, and which can actually be discussed in the context of this podcast. We have to see that all of these aspects, all of these aspects are always relevant due to you saying you find this in your reality, and science says it's actually relevant.
Niels Brabandt EMBA MBA MSc
There's also another aspect where this was particularly important, and it's a movie which I saw due to your recommendations called "Pressure." It's about World War II. It's about James Stack, someone who was a meteorologist and who influenced General Eisenhower to postpone D-Day from June 5 to June 6. And there was a reason why he did that. But let's get into the details here first. What is the situation? So the situation back in the days was that they wanted to have D-Day, the landing in the Normandy to free France, the beginning of freeing France from Nazi rule, was scheduled to take place on June 5, 1944.
Niels Brabandt EMBA MBA MSc
And James Stack, the group captain back then, who by emergency commission held this rank, so who did not become, who did not have this bi-military career, he then said, "We shouldn't do that due to the weather." His counterpart, Colonel Crick from the U.S., said, "They should do, and it's all fine on June 5." And Crick used historic data. He looked at different maps from different years and said, "Look, this was the weather in 1905, 1915, 1925, 1935." So 1944, here we are. And of course, when you now say you can't derive data from history, back in the days, we didn't have the technical means we have today. Very important here. Very important here. So we really need to see that back in the days, this was a common approach.
Niels Brabandt EMBA MBA MSc
Today, of course, we know that weather doesn't reproduce that way, at least not only. We have certain historical data, but it's not the only path we go down today. While Captain Crick - sorry, while James Stack said, "The data doesn't allow that. We should postpone it because on the 5th, there's going to be a massive storm." So we have different anecdotes first. However, Stack's approach was backed by data, while Kirk's approach was backed by anecdotes. Eisenhower then decided to postpone D-Day, and it turned out that on the 5th, there was a massive storm. So if they had landed on that day, probably D-Day wouldn't have been a success.
Niels Brabandt EMBA MBA MSc
And back in the days, people say it's quite likely when D-Day had been a failure that the Nazis had won the Second World War. And by the way, when you think this is not relevant, it is, because without D-Day being a success, France wouldn't be freed. And without France wouldn't be freed, Captain Frederick Hoeffer, U.S. Third Army, wouldn't have had freed concentration camp Buchenwald, where my grandfather, as a resistance fighter - I'm not Jewish, we're German, my family is, but we fought side by side against the Nazis - and my grandfather was freed in 1944, in 1945, by Captain Frederick Hoeffer. And that would have not been possible without a successful D-Day. To wrap the story up, it means without a successful D-Day, I would not sit here today. Let that sink in.
Niels Brabandt EMBA MBA MSc
So General Eisenhower then decided to postpone D-Day, and then someone who was on the part of James Stack, a Norwegian meteorologist, I think his name was Sverre Pettersen, as far as I remember, Sverre Pettersen said that he sees, he sees a gap in, he sees a gap in the data, which means the data says there could be, there potentially could be a gap between two storms. So now, of course, you wonder, "Well, this is about people's lives." So when people land and it doesn't go well, how do you want to know if this is actually - I just looked it up, the name is Sverre Pettersen.
Niels Brabandt EMBA MBA MSc
So they presented the data, and now Eisenhower had to decide, does he follow Kirk, who was successful back in the days on anecdotal evidence, or does he follow Stack? And he decided to follow Stack. So he then went in on 6 a.m. in the morning, the following morning, on June 6, because at 4:15 a.m. he gave the order to start D-Day. And what happened is that the storm cleared up, there was a gap, they could land, and of course, the Nazis didn't expect someone in that weather to arrive, and then everything was a success from there. Fort Hall was established on all beaches, and then France was freed.
Niels Brabandt EMBA MBA MSc
So we see here that as soon as you go into the data, it's the harder way, but it is the better way. Anecdotes can be the start. I can give you an example. An anecdote can be when someone - by the way, for example, when we research, when we research side effects of drugs, we use anecdotes. People take a certain drug in a test group under surveillance, of course, of doctors, and they say, "Hey, this made me a bit dizzy," or, "This made my stomach go weird," or, "I had to throw up from this." Or people say, "Look, I had a bit of a pain in the hand, and with the pill, I still had it, so it didn't have any effect at all." This is anecdotal. However, when you look into evidence, about two-thirds of anecdotal evidence in drug side effect research later is confirmed by rigorous studies. One-third is not.
Niels Brabandt EMBA MBA MSc
So anecdotes are the start. But when you stick to anecdotes and you just rest there, that's always the easy path. Someone said something, and I just follow along. That's just comfortable. It's humanly, personally understandable that you do that, but it's not the best way to approach anything. I'll give you an example. Do you know, especially today, suddenly some of your leaders get to the office and say, "Look, I was at this conference, and one of our competitors said they now do everything in this area with AI. Could you please get us to the same point?" And you just think, "Oh, come on, mate. You just heard something somewhere. This can't be your approach." And see, this is where anecdotes can go wrong. People have to know that anecdotes can be a starting point, but rigorous research has to follow. Data is the better approach. However, sometimes data isn't available. You need anecdotes first to find where the data actually is hidden and where to look at it in the first place.
Niels Brabandt EMBA MBA MSc
And unfortunately, I have to say, I sometimes wonder if with some leaders there is a gap in their education. This is not meant in a condescending way. However, when you say, "I listened to someone and because someone said something, I will simply do the same," that is something where I have to conclude that you have a gap in education. And by the way, just because n equals 1 probably works. So someone says, "I made money investing in Apple." So you invest in Apple and you make money as well. That does not mean someone else does, because past performance doesn't predict future performance, obviously, of any stock or any coin or any investment. So the lack of education here is quite severe. And this is not meant in a condescending way. This can be learned. It's a skill that can be learned, but you have to look into it.
Niels Brabandt EMBA MBA MSc
Let's look into reality. The reality is what you should do is you should act on data. So when, for example, you say, "Oh, they do it with AI, may I see the details here?" And then you do a bit of research and you find out, yeah, so they have one prototype project, which they now are about to launch in a limited test area to see what the results are, and then in the following project, consider if they go live with it. So, oh, that's quite different from they do it with AI. So often the data is different from the anecdote. And sometimes everything goes really well. Many AI projects from big companies went very well. However, also, there are other projects which didn't go too well. For example, the IBM Watson project for clinical analysis with AI to, for example, find different patterns in cancer diagnosis earlier, at the end, it was dodged. It was simply abolished. It was shut down because people found that the data is not sufficient, the forms weren't the ones that the doctors needed, it took all too long, it had too many errors, and that's why they said, "Sorry, it's not working. We need to stick to the old system."
Niels Brabandt EMBA MBA MSc
The reason why, by the way, often people stick to anecdotes and we also have to take this into consideration is, what is the amount of time you have? It's a massive difference if you have six months or six weeks or six days. Or in case of emergency, six hours or maybe six minutes. The more time you have, the better data you will get. Speed is an aspect of the decision-making process here. The quality of your outcome, the quality of your decision is heavily based on the time you have. So, for example, when someone says, "Well, why didn't Eisenhower back in the days consider and got other aspects in and more experts?" Because they didn't have the time. When it's June 4 and you have to decide about the lives of a million people or millions of people, and it's all happening within the next 48 hours because then the tide is not going to be favorable to land for the next two weeks in Normandy, then you do not have the time. It is simply not there. So the quality of your decision is always based on maybe anecdotes available, research data, and the time you have available regarding the speed of your decision.
Niels Brabandt EMBA MBA MSc
Because as soon as you implement, you always have to see one thing. The choice is always with you as a leader. What you cannot do is you cannot say, "I make a decision, and when it goes well, celebrate me." And when it goes wrong, I say, "Look, this team leader gave me the wrong data, and this person implemented the wrong process, and that person did something wrong." What you cannot do as a leader is say, "Celebrate me when I do things right, and I will finger-point at others as soon as they do things wrong, because that's not my accountability. Here's the news, it is." And that is why you see in the movie "Pressure" that, and that's, of course, all historically available, so I'm not telling you any secrets or spoiling anything, that Eisenhower had two statements written if D-Day goes right or D-Day goes wrong. If D-Day went right, the speech is well known in the movie, and you can also see it on YouTube and anywhere else. If things go wrong, he had written, "If anyone did mistakes, it's him and him alone." That is accountability. And by the way, he became the next president of the U.S., just saying here.
Niels Brabandt EMBA MBA MSc
So the choice is always with you. The consequences are as well. That's why you are a leader. That's why you are on leadership pay range, pay grade, and that's why you chose this job. So do not run away from the decision. And by the way, any one of us in life has probably made some bad decisions. And some of them where we even thought, "While we made it, maybe it's not great, but we still did it for whatever reason." And then we have to live up to the consequences. And then we recover from them, and then we move on. That's how democracy works. However, of course, the worse the fault, the more severe the consequences, without any doubt.
Niels Brabandt EMBA MBA MSc
So the decision you have to make is always with you. And as soon as you stick to anecdotes in the beginning, get great data afterwards, then balance it right, get the great advice, and then you get the right decision that actually works not only in the short term, but in the long run. That is a sustainably great decision. And I wish you all the best. Implement this, as we discussed here, in your organization. And when you now say, "Hmm, that sounds quite something. I have about 48 questions here." No problem at all.
Niels Brabandt EMBA MBA MSc
So as soon as you like to have a chat with me, so first, of course, when you now listen to this or you watch this on YouTube, leave a like here, and of course, you can subscribe to my channel. Thank you very much for doing so. Of course, feel free to leave a comment here. Always happy to discuss with you. And of course, you can also leave a review on Apple Podcasts or Spotify, five stars. Thank you very much for doing so. We're growing strongly with this show. We have great rankings again. We'll publish them soon on our Instagram, on our podcast, on our, sorry, on our LinkedIn channel, on my LinkedIn profile. So we are only growing by natural outreach. There is zero penny invested in any kind of paid hour. It's only by well-researched data and a lot of effort, I can tell you. I put into this. So thank you very much for appreciating this. But of course, we are relying on recommendations. So please, if you like what you heard or if you like the channel or whatever else, please recommend this channel to friends, family, online, offline, absolutely anyone out there, because we only grow when you say we should grow.
Niels Brabandt EMBA MBA MSc
And by the way, if you say, "Do you have more than just the weekly format?" Yes, we do. When you subscribe to my YouTube channel, it really pays off to put the tiny bell in there, because then you get a tiny notification when one of our YouTube shorts goes online. We have one leadership tip per day minimum. And that means you can definitely, at any point in time, expect one tip per day. It's either me or a list of hand-selected experts, which I personally vetted. So they are really, they've gone through quite something. Very important is the YouTube shorts here are the ones where you get at least one leadership tip per day. You can, of course, also follow me on Apple Podcasts or Spotify when you now say, "Hey, we need really specific help. We need a trainer, speaker, coach, consultant, mentor, project interim management." Well, that's exactly what I do for a living.
Niels Brabandt EMBA MBA MSc
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Niels Brabandt EMBA MBA MSc
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Niels Brabandt EMBA MBA MSc
By the way, sorry for the ones who couldn't get in last week. For the first time, we reached room capacity. The room has the capacity, and we had a couple of people who simply didn't get in. We never had that before in the history of this channel. We had sessions where we had live sessions with three people in the room this year. So suddenly, I don't know what happened, more people than the room had capacity. So capacity was a thing here. So sorry when you had to stay out last week. Next time, I think we're back to normal. We had a couple of companies that visited with quite a number of people. So only via the leadership letter, expert.nb-networks.com, you receive everything via email and, of course, additional aspects. It's 100% content, ad-free guarantee.
Niels Brabandt EMBA MBA MSc
And of course, you can also contact me via social media, connect with me on LinkedIn, leave a follow on Instagram, or just like me on Facebook, or you can simply go on YouTube and follow my channel there. I'm looking forward to hearing from you. At the end of this podcast and at the end of the video cast, there's always one important thing to say. Apply, apply, apply what you heard in this podcast, because only when you apply what you heard, you will see the positive change that you obviously want to see in your organization. I wish you all the best doing so. If you have any other aspects to talk about, contact me anytime, and no worries, any answer guaranteed within 24 hours or less.
Niels Brabandt EMBA MBA MSc
So at the end of this podcast, as well as at the end of this video cast, there's only one thing left for me to say. Thank you very much for your time.