Spam Filter Batting Average

Wiki Markup\[http://jgc.org/ John Graham-Cumming\] proposed this uniform measure of spam-filter effectiveness in \[http://www.jgc.org/antispam/11162004-baafcd719ec31936296c1fb3d74d2cbd.pdf his November 16, 2004 article entitled 'Understanding Spam Filter Accuracy'\].

Essentially, it's a reformatting of the FalsePositive percentage and FalseNegative percentage, as 'spam hit rate / ham strike rate'. This can be computed from FP%/FN% as follows:

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