In the case of NCO, we note that the 2 Σ + and 2 Π transitions are mainly dominated by singly excited configurations (%T1 = 93.85 and %T1=90.96). Despite that, Loos et al. determined that EOM-CCSDTQ 79 calculations were mandatory to obtain reliable transitions, particularly for the 2 Π state, and that they changed even more for MRCI+Q. Because we cannot fully guarantee the accuracy of the reference or potential problems of the methods for such multi-reference cases, NCO was also regarded as a problematic case in this study. Due to known inadequacies of TD(A)-DFT for closed-shell systems with similar difficulties-double-excitation or high multireference character-previous TD(A)-DHDF studies have presented two separate sets of statistics for the benchmark sets they were investigating, namely with the challenging transitions included and excluded. Here, we follow the same principle. While the previous section provided us with the statistics over 45 excitations of the entire set, this section presents a brief discussion of a reduced set with 41 excitations for 21 radicals. The statistical data for this slightly reduced set are provided in the SI and the relevant results are shown in Fig. . While a recent double-hybrid approach based on the second-order algebraicdiagrammatic construction [ADC (2)] looked promising for double excitations in closed-shell systems, that advantage is expected to also come at a higher computational cost, but could be pursued in a future study.