In an embodiment, a data processing method comprises obtaining a plurality of first transaction data items for a proposed online credit card purchase transaction that has been recommended for review; obtaining a plurality of second transaction data items for a set of similar past online credit card purchase transactions, wherein each member of the set has one or more transaction feature values that are similar to the transaction data items of the proposed online credit card purchase transaction, and a decision value specifying whether the member was accepted or rejected by a reviewer; obtaining a stored data model of features, feature values, transaction acceptance decisions and rejection decisions of the reviewer based at least in part on the set, determining, based on applying the first transaction data items to the stored data model and a subsequent query to the database among more recent transactions that were not included during model construction, a likelihood value of a particular decision of whether the proposed online credit card purchase transaction would be accepted or rejected by the reviewer of the merchant; causing the likelihood value to be displayed; wherein the method is performed by one or more computing devices.