“…Among these are the DIA association factor (Fuhr and Buckley 1991), chi-square (Yang and Pedersen 1997;Sebastiani, Sperduti et al 2000;Caropreso, Matwin et al 2001), NGL coefficient (Ng, Goh et al 1997;Ruiz and Srinivasan 1999), information gain Lewis and Ringuette 1994;Moulinier, Raskinis et al 1996;Yang and Pedersen 1997;Larkey 1998;Mladenic and Grobelnik 1998;Caropreso, Matwin et al 2001), mutual information (Larkey and Croft 1996;Wai and Fan 1997;Dumais, Platt et al 1998;Taira and Haruno 1999) odds ratio (Mladenic and Grobelnik 1998;Ruiz and Srinivasan 1999;Caropreso, Matwin et al 2001), relevancy score (Wiener, Pedersen et al 1995) and GSS coefficient (Galavotti, Sebastiani et al 2000). Three of the most popular methods are descrivbed briefly below.…”