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To facilitate interpretation of the function,we transform according to [[alpha]]1 ß2 1,and find that [[partialdiff]]E [[partialdiff]]R [[partialdiff]]E [[partialdiff]]P when P R ß...E now gives rise to the following special cases:1 When [[alpha]]1 2 ß1 E A [[Delta]]B A B,a normalised symmetric difference between sets A and B A [[Delta]]B A [[union]]B A [[intersection]]B
...2 E >1 R when [[alpha]]>0 ß>,which corresponds to a user who attaches no important to precision
...3 E >1 P when [[alpha]]>1 ß>0,which corresponds to a user who attaches no importance to recall
...It is now a simple matter to show that certain other measures given in the literature are special cases of the general form E
...which is the measure recommended by Heine [3]...One final example is the measure suggested by Vickery in 1965 which was documented by Cleverdon et al
...which is Vickery s measure apart from a scale factor of 100
...To summarise,we have shown that it is reasonable to assume thateffectiveness in terms of precision and recall determines an additive |
