A method for operating authorization rules, comprising: loading into a memory circuit a plurality of authorization rules including a first authorization rule; toggling the first authorization rule between a first mode, that is a prevention mode in which an authorization request is rejected or accepted based on whether the authorization request satisfies the first authorization rule, and a second mode, that is a surveillance mode in which the first authorization rule is not used to reject an authorization based on whether the authorization request satisfies the first authorization rule, over a time interval, wherein the first authorization rule is toggled between the first mode and the second mode during the time interval; receiving , over a network from a plurality of requesting computers, a first set of authorization requests during the time interval; determining a first subset of the first set of authorization requests that satisfy one or more conditions of the first authorization rule; if the first authorization rule is in the first mode, rejecting the first subset of authorization requests; if the first authorization rule is in the second mode, accepting the first subset of authorization requests and confirming , after the time interval, which of the authorization requests of the first set of authorization requests in the first subset accepted in the second mode are valid through an independent process; and determining a first accuracy rate for the first authorization rule based on a portion of authorization requests in the first subset that are valid but would have been rejected in the first mode; and modifying the one or more conditions of the first rule or replacing the first rule based on the first accuracy rate in order to improve the first accuracy rate, wherein toggling the first authorization rule between the first mode and the second mode is based on a target rejection rate which is used to ensure that a certain percentage of authorization requests are not rejected. loading into a memory circuit a plurality of authorization rules including a first authorization rule; toggling the first authorization rule between a first mode, that is a prevention mode in which an authorization request is rejected or accepted based on whether the authorization request satisfies the first authorization rule, and a second mode, that is a surveillance mode in which the first authorization rule is not used to reject an authorization based on whether the authorization request satisfies the first authorization rule, over a time interval, wherein the first authorization rule is toggled between the first mode and the second mode during the time interval; receiving , over a network from a plurality of requesting computers, a first set of authorization requests during the time interval; determining a first subset of the first set of authorization requests that satisfy one or more conditions of the first authorization rule; if the first authorization rule is in the first mode, rejecting the first subset of authorization requests; if the first authorization rule is in the second mode, accepting the first subset of authorization requests and confirming , after the time interval, which of the authorization requests of the first set of authorization requests in the first subset accepted in the second mode are valid through an independent process; and determining a first accuracy rate for the first authorization rule based on a portion of authorization requests in the first subset that are valid but would have been rejected in the first mode; and modifying the one or more conditions of the first rule or replacing the first rule based on the first accuracy rate in order to improve the first accuracy rate, wherein toggling the first authorization rule between the first mode and the second mode is based on a target rejection rate which is used to ensure that a certain percentage of authorization requests are not rejected. <EOS>