The 2(k) factorial design is widely used in simulation experiments involvin
g several factors in which the mean effect, the main effects, and the inter
action effects of these factors are estimated. Previous research has differ
entiated all effects into effects of interest and no interest. Traditional
variance swapping techniques are then used to increase the accuracy of the
estimators of the effects of interest. This article allows one to make a fi
ner distinction among levels of interest. We allow the effects to be divide
d into three groups, say, those of primary interest, secondary interest, an
d little interest. We do this by dividing the class previously labelled as
being of no interest into subclasses of "secondary interest" and "little in
terest". Then we reallocate the relative variances of the estimators of the
effects in the two subclasses. We call this approach a three-class varianc
e swapping technique. (C) 1998 Elsevier Science B.V. All rights reserved.