In view of their excellent performance to cost ratio, the '-3c' family of composite methods developed by Grimme and co-workers is becoming more and more popular. The family includes: HF-3c, PBEh-3c, 37 B97-3c, and the most recent r 2 -SCAN-3c 3 ('a Swiss army knife'), which is built upon the original r 2 -SCAN of Perdew and co-workers. These methods are characterized by small, but carefully chosen set of atomic basis functions, and classical potentials designed to correct their electronic structure part. Boxplots with GEO values of the four 3c methods for B2se are shown in Figure , with B3LYP/AVTZ and B3LYP/AVDZ boxplots shown for comparison. From this figure, we can see that with way larger GEO values, HF-3c stands out from the other three 3c methods. These three 3c methods have similar mean GEO values, with B97-3c having the lowest mean GEO , and r 2 -SCAN-3c having the smallest spread. The three 3c methods are much better than B3LYP/AVDZ, but get beaten by B3LYP/AVTZ. Thus, they overall give highly accurate B2se structures relative to their high efficiency.