Copyright © Erik Hollnagel 2020
All Rights Reserved.
The chief motive of all human actions is the desire to avoid anxiety.
Ibn Hazm (994-1064)
The ETTO Principle - Efficiency-Thoroughness Trade-Off
ETTOing well is the pathway to glory;
ETTOing badly will make you feel sorry!
It is a fundamental characteristic of human performance, whether individual or collective, that the resources needed to do something often, if not always, are too few. The most frequent shortcoming is a lack of time, but other resources such as information, materials, tools, energy, and manpower may also be in short supply. We nevertheless usually manage to meet the requirements to acceptable performance by adjusting how we do things to meet the demands and the current conditions - or in other words to balance demands and resources. This ability to adjust performance to match the conditions can be described as a trade-off between efficiency and thoroughness.1 The essence of this balance or trade-off between efficiency and thoroughness is described by the ETTO principle, which, in its simplest possible form, can be stated as follows: In their daily activities, at work or at leisure, people (and organisations) routinely make a choice between being effective and being thorough, since it rarely is possible to be both at the same time. If demands to productivity or performance are high, thoroughness is reduced until the productivity goals are met. If demands to safety are high, efficiency is reduced until the safety goals are met.
The ETTO principle refers to the fact that people (and organisations) as part of their activities frequently – or always – have to make a trade-off between the resources (primarily time and effort) they spend on preparing to do something and the resources (primarily time and effort) they spend on doing it. The trade-off may favour thoroughness over efficiency if safety and quality are the dominant concerns, and efficiency over thoroughness if throughput and output are the dominant concerns. It follows from the ETTO principle that it is never possible to maximise efficiency and thoroughness at the same time. Nor can an activity expect to succeed, if there is not a minimum of either.
The ETTO fallacy is that people are required to be both efficient and thorough at the same time – or rather to be thorough when with hindsight it was wrong to be efficient!
(1) Simplifying the characterisation of human performance to a trade-off between efficiency and thoroughness is, of course, itself an example of such a trade-off.