The Doorman Fallacy
Never reduce a role to its one obvious function before you cut it
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 92%
The Doorman Fallacy is the mistake of defining a role by its single obvious function, then optimising or automating on that basis. A five-star hotel doorman notionally 'opens the door', so consultants replace him with an automatic door and book a saving. But the doorman also signalled status, provided security, gossiped with regulars and justified the room rate. Five years later the rack rates have collapsed and vagrants sleep in the entrance. The mechanistic model captured only what was measurable and legible, so the invisible functions were destroyed unnoticed. The fix is to map the full function set, including the tacit and status roles, before touching anything, and to price the second-order consequences against the first-order saving.
Origin
Rory Sutherland coined the term from watching consulting firms justify automation projects by reducing complex roles to a single defined task. Extracted from Deep Dive with Ali Abdaal.
Core principles
- 01Most roles do far more than their job title implies
- 02Mechanistic models capture only the measurable functions
- 03Tacit value is real value even when it never appears on a spreadsheet
- 04Efficiency savings can quietly destroy the thing that made you premium
How to run it
- 1
State the notional function
Write down the one thing everyone assumes the role or feature is 'for'.
Pro tip If it fits in three words, you are almost certainly missing something.
- 2
Map the tacit functions
List everything else it does: signalling, security, status, relationships, reassurance, serendipity.
Pro tip Ask front-line staff and customers, not the procurement team.
Watch out The most valuable functions are often the least documented.
- 3
Trace the lag
Work out who would feel the loss and how long before the damage becomes visible.
Watch out Damage often appears years after the saving is booked, so nobody connects the two.
- 4
Price the second-order cost
Weigh the measurable saving against the full downstream consequences of losing the tacit functions.
Pro tip A 50% fall in rates dwarfs a 5% cost saving.
- 5
Decide with the full map
Only automate or cut once the complete function set is visible and the trade-off is honest.
Pro tip Augmenting a role usually beats replacing it.
In the wild
Consultants define a hotel doorman's role as opening the door and replace him with an infrared sliding door, booking a five-year saving. The procurement team applauds. Five years later the doorman's uncaptured functions, status signalling, security, recognising regulars, maintaining the £400-a-night promise, are gone, rack rates have halved and vagrants sleep in the entrance.
→ A booked efficiency saving destroyed far more value than it captured.
Pay-by-app parking arrives as a welcome option. Then the coin machines are removed and the app becomes the only way to pay, so Rory's 92-year-old father with no smartphone can no longer use the car park at all. The 'saving' quietly excluded a whole class of user.
→ An option that improved things became mandatory and cut off part of the market.
Common mistakes
Trusting the mechanistic model
Treating a business like a machine where every part has exactly one function ignores the tacit roles that hold it together.
Confusing an option with a replacement
Technology as an added option is welcome; the same technology as a forced replacement often destroys value for a whole segment.
Is it for you?
Best for
Leaders and consultants weighing automation, cost-cutting, or a 'tidy up' of anything whose real value is partly invisible.
Not ideal for
Genuinely single-purpose commodity tasks with no tacit or status dimension.
From the transcript
“this is what I call the dormant fallacy... you Define the Dorman's role as opening the door”
“the rack rates now fallen by 50 and their vagrants asleep in the hotel entrance because the doorman was doing lots of other things which…”
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Rory Sutherland