4. A system according to claim 3 , wherein the similarity metric is calculated according to the following equation: cos ⁢ ⁢ σ AB = 〈 S → A · S → B 〉  S → A  ⁢  S → B  where cos σ AB comprises a similarity between uncoded electronically stored information item A and reference electronically stored information item B, {right arrow over (S)} A comprises a score vector for uncoded electronically stored information item A, and {right arrow over (S)} B comprises a score vector for reference electronically stored information item B.
3. A system according to claim 1 , further comprising: a score module to form a score vector for each uncoded electronically stored information item and each reference electronically stored information item; and the similarity module to calculate a similarity metric by comparing the score vectors for the uncoded electronically stored information items and the reference electronically stored information items.