Looking at the MAPE for all the singly-excited states, one can see excellent results for Q-CCSD (15.2%), and E-CCSD (20.2%). The other wavefunction methods deliver worse performances, resulting in MAPE of 43.9% for Q-CC2 and 57.1% for I-ADC2. TD-DFT again outperforms the second-order methods but remains less accurate than the CCSD variants, following the order: CAM-B3LYP (34.6%), BH&HLYP (39.3%), LC-BLYP33 (42.7%), LC-BLYP47 (43.2%), and B3LYP (55.6%). Looking at 𝑅 2 , we observe that all the methods have excellent 𝑅 2 values for the whole set of molecules, ranging from 0.99 for Q-CCSD to 0.87 for LC-BLYP33. Interestingly, the methods that underperform on absolute and percentage errors, namely Q-CC2, I-ADC2, and B3LYP, do provide 𝑅 2 close to 1.