Evaluating the effectiveness of ACAs 2.27 The ACA Oversight Committee initiated work into evaluate the effectiveness of ACAs in meeting their objectives. 60 After more than two years, this evaluation is scheduled for consideration in late. While it had been intended to include income tax, GST, excise and PRRT, the evaluation has subsequently been undertaken for income tax ACAs only. 59 Further, the ACA Oversight Committee had not met its charter requirement to report on progress and outcomes of an endorsed work program on a quarterly basis to the Large Market Committee, prior to the Large Market Committee being disbanded in February 2014. 60 Rather than having stated objectives, the key documentation (particularly the Large Business Annual Compliance Arrangements process map) refers to the benefits of ACAs, to both the taxpayer and the ATO. Management Arrangements ANAO Report No 2014–15 Annual Compliance Arrangements with Large Corporate Taxpayers 49 2.28 The ATO has also conducted a series of reviews into ACAs and associated compliance approaches for large corporate taxpayers, as noted in Chapter 1. These reviews have collected information largely from ATO compliance officers and executives about their experiences and perceptions of the benefits and effectiveness of ACAs. 61 As part of the ACA review, in June 2014 the ATO surveyed suitable companies that had not entered into ACAs to ascertain the main reasons for them not participating. These various sources of information have provided a qualitative overview of the effectiveness of key aspects of ACAs, which the ATO has considered in the ACA review, and are discussed in paragraphs 2.32 to 2.38. 2.29 The ATO advised that it faces challenges in evaluating ACAs, such as measuring the additional revenue from, or improved compliance by, large corporate taxpayers as a result of ACAs, or concepts such as certainty and improved cost effectiveness. 62 However, quantitative data is available to support analysis of changes in the tax paid by and compliance performance of taxpayers before and after entering into an ACA, and a range of qualitative information is also available. To provide a defensible opinion about the effectiveness of ACAs, the ATO could apply the principles and guidelines for conducting evaluations set out in its compliance effectiveness methodology. 63 Conducting such an evaluation that includes all relevant taxes may also help to determine the continuing relevance and positioning of ACAs.