" IRS relies extensively on IT systems to annually collect more than $2 trillion in taxes, distribute more than $300 billion in refunds, and carry out its mission of providing service to America's taxpayers in meeting their tax obligations. For fiscal year 2014, the agency's budget request is $2.6 billion for IT. Given the size and significance of IRS's IT investments, and the challenges inherent in successfully delivering these complex IT systems, it is important that Congress be provided reliable cost, schedule, and scope information to assist with its oversight responsibilities. Accordingly, GAO's objectives were to (1) summarize the reported cost and schedule performance for IRS's major IT investments and assess the reporting of the performance information (2) for selected investments, evaluate the reliability of reported cost and schedule variances; and (3) determine IRS's progress in implementing a quantitative measure of functionality delivered for projects. To address these objectives, GAO reviewed documentation, including monthly cost and schedule variance reports, and interviewed staff, including those from selected investments which are critical to IRS's mission. "