Throw the light on merits and demerits of quartile deviation

Merits of quartile deviation are
(i) It is easy to calculate and understand.
(ii) It is less affected by the extreme values of the series.
Demerits of quartile deviation are
(i) Quartile deviation ignores half the items i.e., first 25 % and the last 25 %.
(ii) This method does not show complete formation of the series.