Given that Tr[ 2 ∆] = (1 -1 Γ) 1 Γ, i.e. is computable from the 1-RDM alone, this quantity is arguably the most practical for electronic structure calculations of pure states which do not suffer from a non-uniqueness of the natural orbitals at a particular geometry as in the case of stretched H 2 . In the natural spin orbital basis, Tr[ 2 ∆] = -N basis p=1 1 γ p (1 -1 γ p ), where it is evident that the trace takes on its maximal value when all NOONs are equal (i.e. when the wavefunction is a superposition of equi-probable many-body basis states). As pointed out previously, the squared Frobenius norm of 2 ∆ avoids this issue entirely and is generalizable to open/mixed systems while the trace is not. Importantly, both Tr[ 2 ∆] and || 2 ∆|| remain robust metrics of strong correlation even when the NOON spectrum alone fails to distinguish cases such as square and trapezoidal H 4 . In conclusion, after giving a critical overview of different conceptions of strong correlation, we find that the statistical interpretation offered by the trace or square norm of the cumulant of the 2-RDM is rigorously defined, physically meaningful, and computable. We have shown that for a strongly interacting 6-site Hubbard model (half-filled, at large U/t) and for a number of molecular reaction coordinates involving challenging electronic structure regimes, these metrics based on ∆ indicate what can be justifiably viewed as strong correlation. In addition, a salient result of our work is that we build a bridge between the rather mysterious chemical concept of antiaromaticity and our view of strong correlation.