This paper discusses the application of generalised linear methods to
bilinear models by criss-cross regression. It proposes an extension to
segmented bilinear models in which the expectation matrix is linked t
o a sum in which each segment has specified row and column covariance
matrices as well as a coefficient parameter matrix that is specified o
nly by its rank. This extension includes a variety of biadditive model
s including the generalised Tukey degree of freedom for non-additivity
model that consists of two bilinear segments, one of which is constan
t. The extension also covers a variety of other models for which least
squares fits had not hitherto been available, such as higher-way layo
uts combined into the rows and columns of a matrix, and a harmonic mod
el which can be reparameterised so a lower rank fit is equivalent to a
constant phase parameter. A number of practical applications are prov
ided,including displaying fits by biplots and using them to diagnose m
odels.