There is a question I often ask when I’m running one of my project management courses, and after all these years I still enjoy listening to the answers because they’re almost always the same. I simply ask, “What usually causes projects to run into trouble?”
It doesn’t take long before someone blames poor planning. Another person talks about unrealistic deadlines. Somebody else mentions changing requirements, difficult stakeholders or a lack of resources. Before long the flipchart is covered with perfectly sensible answers, and nobody in the room would disagree with any of them.
Then I ask a second question.
“Yes…but why did those things happen?”
That’s normally the point where the room goes quiet.
People stop looking at the flipchart and start thinking instead. They begin replaying projects they’ve worked on, trying to work backwards from the problem to whatever caused it in the first place. It’s one of my favourite moments because that’s when people stop thinking about project management theory and start reflecting on real life.
Over the years I’ve come to believe that many of the problems we blame for projects going wrong are not actually the root cause at all. They’re simply the symptoms.
Somewhere much earlier in the project, often during those enthusiastic planning meetings when everyone is full of optimism and eager to get started, somebody made an assumption. It sounded perfectly reasonable, nobody challenged it and the meeting moved on. A week later the project plan was signed off, everyone congratulated themselves on a productive planning session and the project got underway.
Weeks or even months later, that innocent little assumption quietly came back to haunt them.
Why Project Assumptions Cause More Problems Than Most Project Managers Realise
One of the reasons assumptions are so dangerous is that they don’t look dangerous. If somebody walks into a meeting and announces that there’s a major technical risk, everybody immediately sits up a little straighter.
Questions start flying around the room. How likely is it? What happens if it materialises? Is there a contingency plan? Risks have a habit of announcing themselves very loudly, so they naturally receive plenty of attention.
Assumptions are much cleverer than that.
They quietly slip into the conversation disguised as common sense.
Imagine you’re sitting in a planning meeting and someone casually remarks that the supplier should have no difficulty delivering the equipment by the end of next month. It sounds perfectly reasonable, so nobody gives it a second thought. A little later someone else comments that the customer almost certainly has all the information ready for the data migration.
Again, it sounds plausible enough, so the discussion moves on. Before the meeting finishes, somebody confidently predicts that Finance won’t have any problem approving the budget because they approved something similar last year.
If you’d been sitting in that meeting, would you have challenged any of those statements?
Probably not. Neither would most people.
That’s precisely why assumptions have a habit of slipping past us unnoticed. They sound so believable that we quietly accept them as facts, when in reality they’re nothing more than educated guesses.
I’ve often compared assumptions to the foundations of a house. When you visit a beautiful home, you admire the architecture, the kitchen, the garden or perhaps the view from the living room window. Nobody ever says, “What magnificent foundations you’ve got.” Yet everyone understands that if those unseen foundations aren’t solid, cracks will eventually begin appearing throughout the building.
Projects behave in exactly the same way.
A project can have an experienced team, an enthusiastic sponsor and what appears to be a well thought-out schedule. Everything looks healthy on the surface. Then, almost without warning, the supplier slips a delivery date, the customer reveals that half the data needs cleaning, a specialist engineer becomes unavailable or an important approval takes far longer than anyone expected.
People often describe those events as surprises, but I’m not always convinced they were.
Quite often they were simply assumptions that nobody ever stopped to question.
Why Every Project Starts with Assumptions… And Why That’s Perfectly Normal
Now, before you decide that assumptions are somehow the enemy, let me reassure you because that’s absolutely not what I’m saying. Every project I’ve ever managed has started with assumptions, and I would confidently predict that every project you’ll ever manage will do exactly the same.
The simple reason is that projects deal with the future, and none of us has the luxury of perfect information. If we waited until every uncertainty had disappeared before writing a project plan, we’d still be sitting in the planning meeting six months later wondering when the project was actually going to begin.
Think about something completely unrelated to project management. Imagine you’re organising a family holiday.
Before you’ve even booked a flight, your brain has already started making assumptions:
- You’re assuming everyone can get the same week off work.
- You’re assuming your passports are still valid.
- You’re assuming the airline will still be flying that route next summer
- You’re probably even assuming that the beautiful photographs on the hotel’s website bear at least some resemblance to reality.
Without those assumptions, you’d never begin planning the holiday. Projects are exactly the same.
The difference is that projects usually involve more people, more money and much bigger consequences when one of those assumptions eventually turns out to be wrong.
That’s why I don’t waste time trying to eliminate assumptions because it simply can’t be done. Instead, I encourage Project Managers to think about them differently.
Rather than pretending they don’t exist, acknowledge them, write them down and gradually replace them with facts as the project develops. That one change in thinking can transform the quality of your planning.
The First Habit That Changed the Way I Managed Projects
Looking back, I honestly can’t tell you when I first developed this habit, but I can tell you it has saved me from countless problems over the years.
Whenever somebody in a planning meeting uses the words “I think…”, “We should…”, “It’ll probably…” or “We’re assuming…”, a little alarm bell starts ringing in the back of my mind.
Not because I think they’re wrong. Not because I enjoy slowing meetings down.
Simply because experience has taught me that those innocent little phrases are often pointing towards something that deserves another question.
So instead of nodding and moving on, I’ll usually smile and ask one of the simplest questions in project management.
“How do we know?” Not, “Are you wrong?” Not, “Can you prove it?”
Simply, “How do we know?”
It’s remarkable how often the room goes quiet. And in that silence, the real planning usually begins.
When an Assumption Gradually Becomes a Risk
One of the things that fascinated me as my career developed was discovering that assumptions don’t suddenly become risks at a precise moment in time. If only project management worked like that, life would be wonderfully simple.
Unfortunately, projects have a habit of changing so gradually that we often fail to notice something important has happened until we’re already dealing with the consequences.
I remember one particular project where we were planning to introduce a new engineering system. As part of the resource planning, we’d identified a specialist engineer whose knowledge would be essential during the final stages of the implementation.
Nobody questioned that decision because it made perfect sense. The engineer had supported similar projects before, everyone expected them to be available and, quite naturally, the project schedule evolved around that assumption.
If you’d asked me during those early planning meetings whether we were making an assumption, I’m not sure I’d even have thought of it in those terms. It simply felt like a sensible expectation based on everything we knew at the time.
Several weeks later we were holding one of our regular progress meetings when someone casually mentioned that the engineer had applied for another position within the company. It wasn’t dramatic. In fact, the comment was almost lost amongst the many other updates that were being discussed. Most people in the room probably regarded it as an interesting piece of gossip before moving on to the next agenda item.
For some reason, I couldn’t let it go.
Not because I believed the engineer was definitely leaving, and certainly not because I wanted to create unnecessary concern. It was simply one of those moments where experience quietly tapped me on the shoulder and suggested we ought to think a little more deeply before moving on.
The assumption we’d been making for weeks hadn’t suddenly become wrong. Nothing had actually changed.
The engineer was still part of the organisation, still expected to support the project and, for all we knew, would still be sitting at the same desk six months later. What had changed was something much more subtle.
For the first time, we’d been given a reason to question an assumption that, until that moment, nobody had thought to challenge. That small change in thinking completely altered the conversation.
Instead of talking about resource allocations as though they were fixed, we started discussing what we would do if circumstances changed.
- Was there another engineer who could support the project if necessary?
- Could some of the specialist work be brought forward while we still had access to the expertise?
- Were there activities elsewhere in the schedule that would give us a little breathing space if we suddenly found ourselves short of resources?
Nobody was predicting disaster. Nobody was panicking.
We were simply recognising that a comfortable assumption deserved another look.
As it happened, the engineer never left. They stayed with the organisation, completed their work on the project and all the contingency planning turned out to be unnecessary.
Or did it?
I’ve heard people describe discussions like that as a waste of time because the problem never actually materialised.
I’ve never seen it that way.
To me, those ten minutes represented good project management at its very best. We didn’t wait until a problem landed on our desk before deciding how to respond.
We used a small piece of new information to ask ourselves whether yesterday’s assumptions still deserved our confidence. The fact that our contingency plans were never needed didn’t make the discussion pointless. If anything, it reinforced the value of thinking ahead while there was still time to influence events.
Looking back over my career, I’ve come to realise that this is often where experience quietly changes the way a Project Manager thinks.
New Project Managers tend to see assumptions, risks and issues as three separate topics because that’s how they’re presented in many textbooks.
Experience gradually teaches you that real projects don’t behave quite so neatly. Assumptions evolve. Some quietly disappear because they prove to be true. Others slowly gather enough uncertainty to become genuine risks. If nobody notices that change taking place, today’s comfortable assumption can very quickly become tomorrow’s project issue.
Why Good Project Managers Keep Looking Back at Their Assumptions
One mistake I certainly made early in my career was assuming that, once the planning was complete, I could file my assumptions away with the rest of the project documentation and get on with delivering the project.
It didn’t take me very long to discover how naïve that was.
Projects are living things. They change constantly because the world around them changes constantly. New stakeholders arrive, suppliers encounter problems, legislation changes, budgets are revised and customers often discover they need something slightly different from what they originally requested.
Every one of those changes has the potential to affect assumptions that seemed perfectly reasonable only a few weeks earlier.
That’s why I gradually developed the habit of revisiting assumptions whenever we held a project review meeting. I never made a major event of it, and I certainly didn’t encourage endless discussions about hypothetical situations.
Instead, I’d simply ask whether anything had happened since our last meeting that made us look differently at the assumptions we’d been working with.
Most of the time the answer was reassuringly boring. Nothing had changed. Excellent. We moved on.
Every now and again, though, someone would say something that made the room stop and think.
“I don’t think we can rely on that anymore.”
Those six words often turned out to be far more valuable than the entire project status report because they signalled that something important had shifted beneath the surface of the project.
I’ve often thought that’s where the real value of assumption management lies. It’s not another register to maintain. It’s not another document to update.
It’s simply a gentle reminder that projects are constantly changing, and good Project Managers change their thinking as the evidence changes around them.
What I’d Like You to Take Into Your Next Project
Whenever I finish talking about assumptions on one of my courses, I usually look around the room and say something that surprises people.
I tell them that I don’t really mind whether they remember the theory we’ve just discussed.
Now, that probably sounds like a strange thing for an instructor to say, but hear me out.
The theory is useful because it gives us a common language, but projects aren’t delivered by theory.
They’re delivered by people sitting around tables, making decisions, solving problems and, every now and again, making assumptions without even realising they’re doing it.
That’s why I’ve always believed the real value of project management lies in changing the way we think rather than simply increasing the number of techniques we know.
If this article has achieved anything, I hope it has encouraged you to become just a little more curious. Not suspicious, because there’s a world of difference between those two words, but curious enough to pause occasionally and ask yourself whether the project is being driven by facts or by expectations that nobody has yet taken the trouble to confirm.
I’ve found that one small change in attitude has a remarkable effect on the quality of project planning. Once people realise it’s perfectly acceptable to question an assumption, conversations become richer.
Team members begin sharing information that might otherwise have remained hidden.
Small uncertainties are brought into the open while they’re still easy to deal with, and problems that could have appeared halfway through the project are often discovered when they’re still no more than a line on a planning document.
It’s rather satisfying when that happens because nobody outside the project team will ever know you’ve quietly prevented a problem that never had the chance to occur.
There won’t be congratulations from senior management because, from their point of view, nothing happened. Yet that’s often what good project management looks like.
Success isn’t always about solving dramatic problems. Quite often it’s about quietly preventing them from appearing in the first place.
The Monday Morning Habit I’d Like You to Try
So, let me leave you with something practical.
The next time you find yourself sitting in a project planning meeting, don’t worry about introducing a new methodology or asking everyone to complete another document. Just listen carefully to the language people use.
You’ll hear phrases like, “I’m sure that’ll be fine,” or, “They’ve always delivered on time,” or perhaps, “We shouldn’t have any difficulty getting approval.” None of those statements is necessarily wrong, and I certainly wouldn’t interrupt every meeting to challenge them.
What I would do is become interested in them because experience has taught me that they often point towards assumptions that haven’t yet been tested.
When you hear one of those comments, don’t turn it into an interrogation. Simply ask the sort of question that keeps a conversation moving rather than bringing it to a halt:
- Ask how the team knows that the information is correct.
- Ask whether anyone has already confirmed it. Ask whether circumstances have changed since the project was first planned.
Those questions don’t create conflict. They create understanding, and understanding nearly always leads to better decisions.
You’ll be amazed how often somebody around the table says, “Actually, I don’t think we’ve checked that yet.”
That’s not bad news. That’s good project management.
You’ve just discovered something while there’s still time to do something useful about it.
A Final Thought Before We Part Company
As I look back over the many projects I’ve been fortunate enough to work on, I honestly can’t remember many occasions when a project failed because people didn’t know enough project management theory.
Most of the difficulties arose because people were working with incomplete information, making perfectly reasonable assumptions and then forgetting that assumptions have a habit of changing as projects move forward.
Perhaps that’s why I’ve never regarded assumptions as something to fear. They’re simply part of managing projects because projects are all about the future, and the future rarely gives us all the answers at the beginning.
The skill isn’t eliminating assumptions because that would be impossible. The skill is recognising them, talking about them and making sure they gradually give way to facts as the project develops.
If you take nothing else away from this article, I’d like it to be this.
The next time somebody says, “We’re assuming…”, don’t immediately decide whether they’re right or wrong.
Instead, smile to yourself and think, “That’s interesting. I wonder how we know.”
You may find that one small question prevents your next project from becoming your next project recovery.
