Definition of efficiency

The word efficiency has its origins in the term latin efficientĭa and refers to the ability to have someone or something to achieve a particular effect. The concept also tends to be compared to that of action, force or production. In other words, efficiency is the rational use of the means that are available to achieve objectives in advance. It's the ability to achieve the objectives and goals envisaged while minimizing the committed resources and time, and thus their optimization.
The efficiency is used in various frameworks. In physics, for example, the efficiency of a process or a device is the ratio of useful energy and energy invested/spent.
In economics, one speaks of the efficiency1 (or optimum) Pareto which is a concept enunciated by Vilfredo Pareto. In this sense, an optimum is a State in which it is impossible to improve the well-being of a person without damaging someone other. A Pareto optimal is based on criteria of usefulness, because from the moment something generates the effectiveness of convenience (comfort) or brings fruits without prejudice to others, a natural process of optimization is raised up to reach the optimum point.
An example of Pareto efficiency can be illustrated thus: a man goes to a shop to buy a computer. Each of them has several technical characteristics and its own price, who usually has to do with the quality. Thus, when the buyer decides to carry out its acquisition, two possibilities can be envisaged:
One hand, it is possible that this person has enough money to buy the best computer without having to worry about because of the price. This is a problem which is said to be single-lens, given that the only goal is to find the computer with the best technical characteristics.
On the other hand, it is possible that the buyer has a fairly tight budget. A multi-objective problem then since this person needs to consider not only the technical characteristics, but also the price of the product. In this case, there is no optimum product but rather multiple Pareto-optimal solutions.