A method for generating access rules, the method comprising performing by a computer system: storing access request information including a plurality of previously received access requests, each previously received access request having a plurality of access request parameters; storing validity information corresponding to the plurality of previously received access requests, the validity information indicating whether each access request is fraudulent or legitimate; selecting a first parameter and a second parameter from the plurality of access request parameters, the first parameter associated with a first set of conditions, the second parameter associated with a second set of conditions; determining a plurality of mutually exclusive segments based on the first set of conditions and the second set of conditions, wherein each segment is associated with one condition of the first set of conditions and one condition of the second set of conditions; generating a plurality of potential access rules, each potential access rule corresponding to a different segment of the plurality of mutually exclusive segments, each of the potential access rules having the conditions of the corresponding segment; determining a predictive percentage for each of the potential access rules based on the validity information corresponding to previously received access requests having one or more parameters that involve the conditions of the potential access rule; selecting one or more of the potential access rules to be included in an operational set of access rules based on the predictive percentages for each of the potential access rules; receiving, over a network from a plurality of devices, a plurality of real-time access requests; accessing a system memory to obtain the operational set of access rules when one of the plurality of real-time access requests is received from a first device of the plurality of devices; using the operational set of access rules to determine access request outcomes for the real-time access requests; and providing access to a resource based on the access request outcomes. storing access request information including a plurality of previously received access requests, each previously received access request having a plurality of access request parameters; storing validity information corresponding to the plurality of previously received access requests, the validity information indicating whether each access request is fraudulent or legitimate; selecting a first parameter and a second parameter from the plurality of access request parameters, the first parameter associated with a first set of conditions, the second parameter associated with a second set of conditions; determining a plurality of mutually exclusive segments based on the first set of conditions and the second set of conditions, wherein each segment is associated with one condition of the first set of conditions and one condition of the second set of conditions; generating a plurality of potential access rules, each potential access rule corresponding to a different segment of the plurality of mutually exclusive segments, each of the potential access rules having the conditions of the corresponding segment; determining a predictive percentage for each of the potential access rules based on the validity information corresponding to previously received access requests having one or more parameters that involve the conditions of the potential access rule; selecting one or more of the potential access rules to be included in an operational set of access rules based on the predictive percentages for each of the potential access rules; receiving, over a network from a plurality of devices, a plurality of real-time access requests; accessing a system memory to obtain the operational set of access rules when one of the plurality of real-time access requests is received from a first device of the plurality of devices; using the operational set of access rules to determine access request outcomes for the real-time access requests; and providing access to a resource based on the access request outcomes.