01233nas a2200217   4500000000100000000000100001008004100002653001500043653002200058653002000080653002000100653002100120653001900141100001900160700001700179700002100196245003700217300001200254490000700266520074200273       2004                            d10aBlacklists10aDecision Analysis10aFalse Negatives10aFalse Positives10aNetwork Security10aSpam Detection1 aAgustin Orfila1 aJavier Carbo1 aArturo Ribagorda00aDecision Model Analysis for Spam  a151-1610 v153 a<p>One of the security challenges in e-Government is to offer a smooth dialogue with citizens, which guarantees the availability, confidentiality and integrity of the information interchanged. Spam jeopardizes the survival of electronic mail as a communication means. Many approaches to tackle the problem with spam have been proposed. This paper shows the necessity of studying the real value of spam filters. Contrary to common belief, false positive rate and false negative rate do not completely reveal to what extent a junk filter is worth using. Very important parameters like the hostility of the environment (summarized by the probability of receiving spam) or the error costs associated with the filter play a decisive role.</p>