A quartile is a type of quantile. The first quartile is defined as the middle number between the smallest number and the median of the data set. The second quartile is the median of the data. The third quartile is the middle value between the median and the highest value of the data set.


What is a ‘Quartile’

A quartile is a statistical term describing a division of observations into four defined intervals based upon the values of the data and how they compare to the entire set of observations.

Explaining ‘Quartile’

Each quartile contains 25% of the total observations. Generally, the data is ordered from smallest to largest with those observations falling below 25% of all the data analyzed allocated within the 1st quartile, observations falling between 25.1% and 50% and allocated in the 2nd quartile, then the observations falling between 51% and 75% allocated in the 3rd quartile, and finally the remaining observations allocated in the 4th quartile.

Try not to confuse a quarter with a quartile.

Further Reading

  • Study on dynamic factors striding across the middle income Trap-transnational empirical analysis based on quartile regression – www.tandfonline.com [PDF]
  • The probability of publishing in first-quartile journals – link.springer.com [PDF]
  • The cost-effectiveness of replacing the bottom quartile of novice teachers through value-added teacher assessment – www.jstor.org [PDF]
  • Quartiles in elementary statistics – www.tandfonline.com [PDF]
  • How ordinary consumers make complex economic decisions: Financial literacy and retirement readiness – www.worldscientific.com [PDF]
  • Slow and Steady Wins the Race: The Impact of Chasing Returns on Quartile Rankings – papers.ssrn.com [PDF]
  • Comment: How to estimate quartiles using the Blom method – www.tandfonline.com [PDF]
  • Levels of dissociation and nonsuicidal self-injury: A quartile risk model – www.tandfonline.com [PDF]
  • Benchmarks for expected annual academic growth for students in the bottom quartile of the normative distribution – www.tandfonline.com [PDF]