  Electromagnetically induced transparency (EIT) and Autler-Townes splitting
(ATS) are generally characterized and distinguished by the width of the
transparency created in the absorption profile of a weak probe in presence of a
strong control field. This often leads to ambiguities, as both phenomena yield
similar spectroscopic signature. However, an objective method based on Akaike's
Information Criterion (AIC) test offers a quantitative way to discern the two
regimes when applied on the probe absorption profile. The obtained transition
value of control field strength was found to be higher than the value given by
pole analysis of the corresponding off-diagonal density matrix element. By
contrast, we apply the test on ground state coherence and the measured
coherence quantifier, which yields a distinct transition point around the
predicted value even in presence of noise. Our test accurately captures the
transition between two regimes, indicating that a proper measure of coherence
is essential for making such distinctions.
