In summary, the score for an excited state is given by the overlap with a corresponding state of the reference calculation, minus (∆E)/2, minus (∆|TDM|)/3. The scaling of ∆E and ∆|TDM| were empirically chosen to not penalize excessively due to energy and intensity differences, and to give a bigger weight to the first over the second. While the scoring system is straightforward to use in terms of relative accuracy between two or more methods or functionals, it is less trivial to identify a threshold for an excited states calculation to be considered overall generally accurate. Obviously, there is not a general answer and it depends on the method considered. The strengths of this scoring system are the inclusion of all the terms in one metric and being general and transferable to any electronic structure method; it can detect the absence of double excitation or the presence of spurious charge transfer states or misinterpretation of mixed and pure states; it can be extended to include any number of excited states of any multiplicity, or just focusing on a manifold of states; it easy to interpret and can be applied to compare quickly different methods/functionals. For example, if five excited states are considered, each with a score between 0 and 1, by multiplying by 20, a score between 0 and 100 is given to a calculation, which can be interpreted as the percentage Figure : A summary of DELFI excited states scoring system proposed in this work. First, the overlap matrix between the one-electron transition density matrix of two calculations is calculated. According to the diagonal and/or the off-diagonal values, the matching states between the two calculations are chosen and a partial score is assigned for each state. This partial score is then refined by removing a penalty due to the difference in energy and TDM between the states of the two calculations. A score between 0 and 1 is assigned to each state, which indicates the similarity between the two. Finally, the scores for each state are summed up to give a final score to the excited states calculation.