1. A method for assessing risk associated with a multi-dimensional risk table comprising: approximating an initial risk value for a substantially empty cell in a risk table based upon risk values in cells related to the substantially empty cell; determining an adjustment value for the approximated initial risk value; and applying the adjustment value to the initial risk value to yield a final approximate risk value for the previously substantially empty cell, the final approximate risk value being used subsequently in a statistical model, the statistical model enabling a determination to be made whether transaction data is to be classified as fraudulent.