© 1988 by Biometrika Trust
M-quantiles
Australian Bureau of Agricultural and Resource Economics Canberra City, ACT 2601, Australia
It is well known that a M-estimator of the centre of symmetry
of a symmetric distribution can be defined in terms of either a continuous symmetric loss function
or the associated influence function
. This estimator is robust if
is bounded. In this paper, we develop a generalization of the M-concept to estimation of a quantile analogue of
, called a M-quantile, by introducing a particular kind of asymmetry into
. A natural consequence is that the M- quantile parameter then bears the same relationship to
as the ordinary quantile bears to the median. The extension of this idea to the case of multivariate data is considered in some detail. Two applications to the analysis of agricultural survey data are given.
Key Words: Influence curve M-estimation Multivariate data Quantile Regression Robust estimation