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  • Measuring tax gaps in Australia for the goods and services tax (GST) and the luxury car tax (LCT) up to 2010–11

    This information is for historical purposes only.

    Copies of this publication

    You can download a printable version of Measuring tax gaps in Australia for the GST and the LCT (NAT 74422, 1.93MB) in Portable Document Format (PDF).

    The estimated 2010–11 GST gap was provided in the Commissioner of Taxation Annual Report 2012–13. The GST gap for 2010–11 was 6.5% of GST revenue (including debt) or $3 billion. Excluding debt, the GST gap was 5.4% of revenue or $2.5 billion. We will publish an updated paper in January 2014.


    In recent years, we have increased our emphasis on measuring the effectiveness of our activities.

    Tax gap is one of many measures we use to understand the extent our compliance efforts have brought about positive and sustainable taxpayer behavioural changes.

    This paper presents our estimates of the goods and services tax (GST) gap for the period 2001-02 to 2009-10 and luxury car tax (LCT) gap for the period 2009-10 to 2010-11.

    Measurement of the tax gap has long challenged revenue agencies around the world. Estimating the magnitude of, and trends in, tax gaps is inherently difficult.

    These estimates are based on information presently available. The estimates contain a margin of error due to the data sources and assumptions we used when making the estimates.

    Estimates of tax gap may be subject to revisions as new information, new data, and improved understanding of methodologies become available.

    This document summarises our methodology for estimating the GST and LCT gaps. We welcome feedback on this paper from interested parties as we continue to refine this approach.

      Last modified: 13 Nov 2015QC 26611