Statistical Modelling 2 (2002), 333–349

Flexible smoothing with P-splines: a unified approach

I D Currie
Department of Actuarial Mathematics and Statistics,
Heriot-Watt University,
Edinburgh, EH14 4AS,
UK.
eMail:  I.D.Currie@ma.hw.ac.uk

M Durban
Departamento de Estadistica y Econometria,
Universidad Carlos III de Madrid,
Edificio Torres Quevedo,
28911 Leganes,
Madrid,
Spain.
eMail:  mdurban@est-econ.uc3m.es
 

Abstract:

We consider the application of P-splines (Eilers and Marx, 1996) to three classes of models with smooth components: semiparametric models, models with serially correlated errors and models with heteroscedastic errors.  We show that P-splines provide a  common approach to these problems.  We set out a simple nonparametric strategy for the choice of the P-spline parameters (the number of knots, the degree of the P-spline and the order of the penalty) and use mixed model (REML) methods for smoothing parameter selection.  We give an example of a model in each of the three classes and analyse appropriate data sets.

Keywords:

Heterogeneity; mixed models; P-splines; REML; semiparametric models; serial correlation.

Downloads:

Data and Software in zipped archive
back