Each year, we publish an integrated Annual Review. This review provides our stakeholders with information on the opportunities and challenges in our operating environment, and a summary of our strategy and our performance. It's about giving our stakeholders the big picture, beyond just the numbers, and it's a chance for stakeholders to hear directly from our Chairman and Group CEO.
We have engaged both formally and informally with our investors, analysts, employees, consumer advocate groups and community groups to ensure that our Annual Review is focused on the issues that matter most. Our approach has also been informed by the International Integrated Reporting Council's (IIRC) Integrated Reporting Framework. Read more about our Integrated Reporting
Our report includes an independent assurance statement from Ernst & Young and is prepared using the Global Reporting Initiative's Sustainability Reporting Guidelines (G4).
In addition to our integrated Annual Review, we also publish a Dig Deeper paper to provide detailed information on our performance against our corporate responsibility strategy, Wealth of Opportunity and our business-wide commitments. This report details our performance against the material issues as identified through our Annual Materiality Review. Our 2014 GRI Index can also be found on pages 67 -69 of our 2015 Dig Deeper.
We have also published a Group Environmental Performance Summary to provide more in depth analysis of our environmental performance over the 2015 year.
We also look at ways to measure and report the impact of our community programs and initiatives. Since 2012, in partnership with others, we have been measuring the impacts of our community programs using the social return on investment (SROI) methodology. Read more about Impact measurement below.