The efficiency–thoroughness trade-off principle (or ETTO principle) is the

principle A principle is a proposition or value that is a guide for behavior or evaluation. In law, it is a Legal rule, rule that has to be or usually is to be followed. It can be desirably followed, or it can be an inevitable consequence of something, suc ...

that there is a trade-off between

efficiency Efficiency is the often measurable ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do things well, successfully, and without ...

effectiveness Effectiveness is the capability of producing a desired result or the ability to produce desired output. When something is deemed effective, it means it has an intended or expected outcome, or produces a deep, vivid impression. Etymology The ori ...

on one hand, and thoroughness (such as safety assurance and human reliability) on the other. In accordance with this principle, demands for productivity tend to reduce thoroughness while demands for safety reduce efficiency. The ETTO principle was originally proposed by the safety researcher Erik Hollnagel.

In safety

The principle has been applied to analysis of behaviour and choices made regarding safety and risk. There are competing activities requiring time, which is a limited resource. In order to make time available for desirable activities, less time can be spent on preparation and planning, which affects safety. Most of the time the trade-off ends well, and the preferred or profitable activity proceeds without undesirable incident, which is why these trade-offs are so prevalent. Eventually luck may run out and something goes wrong. In hindsight it is often obvious when and where such tradeoffs were made, and the consequences may be clearly linked to causes, but the trade-off seemed like a good idea at the time, and for as long as things kept going right. The principle of requiring "reasonably practicable" precautions in occupational health and safety recognises that such trade-offs must exist to allow economic activity to proceed, and puts the onus on the employer to assess the risk and take those precautions.

References

Economic efficiency {{economics-stub