Programme risk·6 min read
0.5%. That is how many big projects land on budget, on time and on benefits.
Flyvbjerg has the largest dataset on big projects anyone has assembled. The headline number should change how you plan, and usually does not.
Source
How Big Things Get Done
Bent Flyvbjerg & Dan Gardner · Currency / Penguin Random House · 2023
Read the originalAslanWay is not the author of this work. The summary below describes the source; the commentary that follows is ours and is not endorsed by the author.
What it argues
Bent Flyvbjerg spent decades building a database of more than 16,000 major projects across sectors and countries. The summary statistic from that database is brutal: about 8.5% come in on budget and on time, and roughly 0.5% come in on budget, on time and delivering the benefits that justified them.
The book's explanation is not incompetence. It is that planning is treated as an obstacle to be cleared rather than the work itself. Teams commit early, start building to show progress, and then discover the expensive problems with the concrete already poured.
Think slow, act fast
Flyvbjerg's prescription is to spend a large share of the timeline on planning, modelling and iteration — where changes are cheap and reversible — and then to build quickly once the design is genuinely settled. He contrasts projects that iterate in simulation with those that iterate in production.
The second prescription is reference class forecasting: estimate your project by looking at the actual outcomes of similar completed projects rather than by reasoning up from your own plan, which is systematically optimistic.
Modularity is the hedge
Projects built from repeated small units — a solar farm, a data centre hall — behave far better than one-off megaprojects, because each repetition teaches and each failure is contained. That maps almost exactly onto shipping software in vertical slices.
What we do with it
- Reference class forecasting is the cheapest improvement most programmes can make. Before accepting an estimate, ask what actually happened on the last three comparable programmes in the organisation — not what was planned.
- "Think slow, act fast" is not the opposite of shipping early. Both mean the same thing: make the expensive commitments as late and as reversibly as you can, and learn from something real in the meantime.
- If a programme cannot be decomposed into repeating units, that is a risk finding in itself. It usually means the first release is far too big.