Health Economics

  • When a continuous variable is split for convenience into equal-sized chunks of data the cut-off points between them are called quantiles. Thus, if there are four such groups (quartiles), each containing 25 per cent of the data, there are three quantile cut-off points, the central one being the median. Common divisions are tertiles (three groups), quartiles (four), quintiles (five), deciles (ten), centiles or percentiles (100).