## Efficiency

In this chapter, we will use the concept of efficiency to evaluate how well a machine performs its designed task in terms of quantity and/or quality of performance. Owners and managers of farm enterprises are deeply concerned with efficient operation of equipment and other resources because inefficient operation leads to greater operating expenses and reduced profits. Efficiency is usually expressed as a percentage. A percentage is calculated by comparing to quantities and multiplying by 100. Because efficiency is a ratio of two quantities having the same units, the units cancel.

Efficiency can be expressed mathematically in several forms. In the most general terms, efficiency can be expressed as:

output

Efficiency is the ratio of what we get out of something relative to what we put in. If the output is 9 units (pounds, hours, etc.) and the input 10 units, the efficiency is:

output 9

Or, if the output is 5 units and the input 10 units, the efficiency is:

output 5

Efficiency can also be determined by comparing the actual performance to the theoretical performance. This equation is:

actual

theorectical

It is important to remember that an efficiency calculation provides a mathematical answer to a problem. It is only a tool or information that can be used to make a decision. For example, if you determine that the fuel efficiency of an automobile is 20 miles per gallon that is not sufficient information to determine if the automobile is performing satisfactory. This number must be compared to the historical performance, manufacturer's guidelines or other data to make a decision on its acceptability.