A quintile is a statistical value of a data set that represents 20% of a given population. It is a type of quantile, which is defined as equal-sized segments of a population. Quintiles are used to create cut-off points for a given population. For example, a government-sponsored socio-economic study may use quintiles to determine the maximum wealth a family could possess in order to belong to the lowest quintile of society. This cut-off point can then be used as a prerequisite for a family to receive a special government subsidy aimed to help societys less fortunate.

Quintiles are often used in reference to economic differences by politicians and policy-makers. For instance, the top 20% of wage earners might be called the fifth quintile. Health organizations sometimes use quintiles to show distributions of health statuses.

Here are the key points about quintiles:

• A quintile is one of five values that divide a range of data into five equal parts, each being 1/5th (20 percent) of the range.
• The first quintile represents the lowest fifth of the data (1% to 20%); the second quintile represents the second fifth (21% to 40%) and so on.
• Quintiles are used to create cut-off points for a given population.
• Quintiles are often used in reference to economic differences by politicians and policy-makers.
• Health organizations sometimes use quintiles to show distributions of health statuses.