Identifying suspect electronic tax data of an electronic tax return prepared using a tax preparation program. A first field of the tax return is populated with first tax data. The program selects statistical data for another type of tax data based upon the first tax data. A second field is populated with second tax data, which is compared with selected statistical data to determine whether the second tax data satisfies pre-determined criteria relative to the selected statistical data, e.g., whether the second tax data is within a pre-determined range or standard deviation of a mean or average of statistical data. If the second tax data does not satisfy the criteria, e.g., is outside of the range or standard deviation, the program issues an alert to notify the preparer of the specific location of the suspect data. The alert may be issued in real time while the tax return is being prepared.