In some embodiments, a resource security system may determine an access request outcome (e.g., accept, reject, or review) for an access request based on access rules. The resource security system may generate and select the access rules to be used for using stability information. For instance, the resource security system may select a training set from the received access requests, e.g., including recently received access requests, and generate a plurality of potential access rules based on the training set. The resource security system may determine and compare the detection performance and the stability performance of the potential access rules. The resource security system may select the best performing potential access rules to be used in operation for determining the outcome of access requests.