  Dynamical compensation (DC) has been recently defined as the ability of a
biological system to keep its output dynamics unchanged in the face of varying
parameters. This concept is purported to describe a design principle that
provides robustness to physiological circuits. Here we note the similitude
between DC and Structural Identifiability (SI), and we argue that the former
can be explained in terms of (lack of) the latter. We propose to exploit this
fact by using currently existing tools for SI analysis to perform DC analysis.
We demonstrate the feasibility of this approach with four physiological
circuits, for which we confirm the correspondence between DC and lack of SI. We
also warn that care should we taken when using an unidentifiable model to
extract biological insight, since lack of SI can be the result of an
inappropriate choice of model structure and therefore not necessarily a sign of
biological robustness.
