Title: The Dagum regression model in survival analysis
Authors: Mariangela Zenga - Universita degli Studi di Milano-Bicocca -DISMEQ (Italy) [presenting]
Juan Eloy Ruiz-Castro - University of Granada (Spain)
Filippo Domma - University of Calabria (Italy)
Abstract: The Dagum distribution is a Burr III distribution with an additional scale parameter. It is closely related to the Burr XII distribution and, more generally, turns out to be a special case of the Generalized Beta distribution. Even if the Dagum model has been used in studies of income and wage distribution as well as wealth distribution, only recently it was introduced in the field of the survival analysis and the reliability. The hazard rate of this model is very flexible; in fact, it is proved that, according to the values of the parameters, the hazard rate of the Dagum distribution has a decreasing, or a Upside-down Bathtub, or Bathtub and then Upside-down Bathtub failure rate. Moreover some features of this distribution (as the reversed hazard rate, the mean and variance of the random variables residual life and reversed residual life and their monotonicity properties) were studied. We will consider the observed heterogeneity depending on covariates in a regression model with a Dagum distribution.