  Non-standard scenarios described by effective contactlike interactions can be
revealed only by searching for deviations of the measured observables from the
Standard Model (SM) predictions. If deviations were indeed observed within the
experimental uncertainty, the identification of their source among the
different non-standard interactions should be needed. We here consider the
example of the discrimination of gravity in compactified extra dimensions (ADD
model) against the four-fermion contact interactions (CI). We present
assessments of the identification reach on this scenario, that could be
obtained from measurements of the differential cross sections for the fermionic
processes $e^+e^-\to{\bar f}f$, with $f=e,\mu,\tau,c,b$, at the planned ILC.
