Summary: In light of the fourth anniversary of the Internal Revenue Service (IRS) Restructuring and Reform Act of 1998, which established Congress' expectation that IRS modernize to better meet taxpayer needs, GAO gave an overview of IRS's current performance and resources and then assessed the progress that IRS has made modernizing and the risks to continued progress. Overall, IRS has seen increased workload, decreased staffing, and significant changes in the allocation of resources between taxpayer assistance programs and its compliance and collection programs. Between 1995 and 2001, IRS's workload, measured by returns filed, increased by 10 percent while aggregate staffing declined by 14 percent. Over the same time, there was a significant internal reallocation of resources with a disproportionate decline in compliance and collection program staffing to accommodate more emphasis on taxpayer service, such as telephone assistance, and to information systems operation and investment. Electronic filing of returns increased but not enough to reduce paper returns sufficiently to free significant processing resources for use elsewhere. The reallocation of resources shows signs of beginning to produce more accurate service for taxpayers, but the compliance and collection programs have seen large and pervasive declines in performance indicators such as audit rates, collection cases closed, enforcement actions such as liens and levies, and raw productivity.