This paper examines the feasibility and value of using nonparametric v
ariance-based methods to supplement parametric regression methods for
uncertainty analysis of computer models. It shows from theoretical con
siderations how the usual linear regression methods are a particular c
ase within the general framework of variance-based methods. Examples o
f strengths and weaknesses of the methods are demonstrated analyticall
y and numerically in an example. The paper shows that relaxation of li
nearity assumptions in nonparametric variance-based methods comes at t
he cost of additional computer runs. (C) 1997 Elsevier Science Limited
.