A method that includes a first record that relates to a first subject entity is received and a second record that relates to a second subject entity is received, where it is unknown whether the first subject entity is the same as the second subject entity. A comparison of a first external/non-key attribute value for the first subject entity to a second external/non-key attribute value for the second subject entity is performed. A probability value is calculated, at least in part, on a first external/non-key attribute value for the first subject entity to a second external/non-key attribute value for the second subject entity.