|Ratios, Proportions, and Rates|
|Ratios, proportions, and rates are commonly used to describe nominal variables in biomedical research, especially in epidemiological studies. It is worth noting that these three frequency measures are related but different.
They are related, because they have a similar definition: Ratio, proportion, rate=x/y×10n.
They are different concepts in various way.
For a ratio, the values of x and y can be completed unrelated, or related. For instance, a ratio can be female/male; a ratio can also be female/all.
For a proportion, x must be a component of y, thus y has to include x such as female/all.
A rate usually is a proportion, which is defined as the occurrence of x in the y population during a given period of time. Thus, a rate has two aspects: x must be a part of y; x and y are described in the same period of time.
Once we understand the concept of each measure listed above, we can use them correctly in a manuscript.