In this paper we suggest that an extension of a procedure recently proposed
by Wayland et al. [Phys. Rev. Lett. 70, 580 (1993)] for recognizing determ
inism in an autonomous time series can also be used as a diagnostic for det
ermining an appropriate embedding dimension for driven ("input-output") sys
tems. We compare the results of this extension to the results produced by t
he extensions to the method of false nearest neighbors put forward by Rhode
s and Morari [Proceedings of the American Control Conference, Seattle, edit
ed by The American Automatic Control Council (IEEE, Piscataway, 1995)] and
the method of averaged false nearest neighbors by Cao et al. [S1063-651X(99
)12510-8].