1. A computer-implemented method for estimating a value of a transaction-based variable for credit line management, the method being implemented by one or more data processors and comprising: providing, by at least one data processor, a first model for expected future profit that includes a transaction risk score that is controlled by a line increase decision strategy, the transaction risk score modeling features indicative of risk including default probability as a function of transaction time series features; analyzing, by at least one data processor, pooled historical data from a plurality of lenders and relating to a plurality of loan recipients that capture a variety of line increases and identify account behavior before and after a line increase, the analyzing informing the first model; estimating, by at least one data processor, future profit using second models that include and exclude transaction risk score as a data source respectively; and computing, by at least one data processor, the profit difference, the profit difference comprising an estimate of the value created by inclusion of the transaction risk score as a transaction-based variable; wherein the first model is of the form: 
 E profit= f + ( X,CLI;β + ), wherein X=data concerning the customer and wherein X includes the transaction risk score, the transaction risk score being the only transaction-based variable in the model, CLI represents potential credit line increase amounts, and β + =model parameters that use the transaction risk score to contribute to the profit estimate; wherein at least one of the second models is of the form: 
 E profit= f − ( X,CLI;β − ), wherein β − =model parameters that are constrained such that the transaction risk score does not contribute to the profit estimate.