Quartile Deviation : It is based on the lower quartile and the upper quartile. The difference is called the inter quartile range. The difference divided by is called semi-inter-quartile range or the quartile deviation.Thus. The quartile deviation is a slightly better measure of absolute dispersion than the range.But it ignores the observation on the tails. If we take difference samples from a population and calculate their quartile deviations, their values are quite likely to be sufficiently different.t is based on the lower quartile and the upper quartile. The difference is called the inter quartile range. The difference divided by is called semi-inter-quartile range or the quartile deviation. Thus. The quartile deviation is a slightly better measure of absolute dispersion than the range.