In 1993, for the first time in several years, the number of tax returns filed dropped; about 2 million fewer individual income tax returns were filed that year than during 1992. The Internal Revenue Service (IRS) believes that a major reason for the decrease is the change in withholding tables for tax year 1992, which caused fewer taxpayers to receive refunds and more to owe taxes. IRS identified about 54,000 fraudulent returns involving refund claims in 1993, about twice as many as IRS identified in 1992. Fraudulent electronic filing, which has been on the upswing since the service was introduced nationwide in 1990, is a particularly difficult problem for IRS because of the speed with which refunds are processed. Although IRS is bolstering its efforts to combat electronic fraud, such as conducting computer checks to verify that taxpayer names and social security numbers on returns match IRS records, GAO believes that IRS could take further steps to identify and stop fraudulent electronic refunds. For example, IRS should analyze information provided by banks on rejected refund anticipation loans--loans that allow taxpayers to quickly get money while their refunds are being processed. IRS indicators show that, except for the continuing fraud problem, the agency did a good job processing returns during the 1993 filing season; most refunds were issued quickly and accurately. In addition, toll-free telephone assistors did a good job answering tax law questions, and distribution centers did a good job responding to taxpayers' requests for forms, instructions, and publications. Taxpayers, however, continued to have difficulty getting through to telephone assistors.