What’s the issue?

Estimates are a fundamental part of sustainability reporting. They are used in forward-looking information (e.g. forecasts about future planned capital investments to mitigate risks) as well as in data that is primarily historical (e.g. metrics).

Comparative information is important to users’ understanding because it allows trends to be seen. Unlike IFRS® Accounting Standards, under proposed IFRS S11 companies would be required to disclose comparative information that reflects updated estimates. Companies may need to update their estimates due to:

  • changes in calculation methodology;
  • changes in inputs used; or
  • availability of new data sources.

The International Sustainability Standards Board (ISSB) analysis of feedback showed support from users for presenting comparative information that includes updated estimates. However, preparers raised concerns about how they could achieve this in practice – including the cost and complexity of updating all estimates.

The ISSB has confirmed that comparative information will need to be revised for many changes in estimates, but stepped back from requiring revisions related to forward-looking estimates. This is different to the approach for changes in accounting estimates where comparatives are not revised in the financial statements. Companies will need to think carefully about the processes and controls that will be needed.

Irina Ipatova,
Global Corporate & Sustainability Reporting Topic Team

What was proposed?

Comparative information presented for sustainability-related metrics would need to reflect updated estimates in certain circumstances. This requirement would not apply to narrative or descriptive disclosures.
When a company reports comparative information that differs from the information it reported in the previous period, it would disclose:

  • the difference between the amount reported in the previous period and the revised comparative amount; and
  • why the amounts have been revised.

There would be exceptions to these requirements:

  • in the first year of adoption; or
  • when a company cannot collate the required information.

Like IFRS Accounting Standards, there would be separate requirements for when comparative information is updated to correct material errors, or if a metric presented is redefined or replaced.

What’s the ISSB’s latest thinking?

The ISSB confirmed that it would amend the proposal to update estimates in comparatives so that it would apply to estimates for the previous reporting period disclosed in that previous period but would not apply to ‘forward-looking’ estimates. Companies would only be required to update comparative information if the change is material.

The ISSB also discussed providing illustrative examples to support companies in applying the requirements. This may include examples of situations in which a company would be required to revise comparative information to reflect updated estimates.


What’s the impact?

Companies would not need to recalculate comparative information for every metric presented – but they would need to understand the impacts from changes in estimates used to prepare current-year information.

Revising comparative information to reflect certain updated estimates would allow users to compare current-period amounts and those reported in the prior period, based on a consistent basis of estimation while avoiding introducing hindsight bias by updating forward-looking information.

The ISSB will provide further guidance on which estimates would be updated. In the meantime, companies need to consider the practical implications that revising comparatives may have – e.g. on systems or where metrics are linked to remuneration.

Actions for management

  • Familiarise yourself with the proposals. See our guide for more detail.
  • Once you are familiar with the types of metrics that you would present, identify your most sensitive estimates and understand what may cause them to change.
  • Assess whether you have processes, systems and controls in place to monitor and measure changes in your estimates and deal with the practical consequences of revising comparatives.

How did we get here?


Document version Reference
Proposed IFRS S1 ED/2022/S1 Published 31 March 2022
ISSB Board meeting: 18–21 October 2022; Montreal

AP3A: Update to plan for redeliberations 

Meeting summary

The ISSB decided to add one further topic to its plan for redeliberations relating to the requirement in proposed IFRS S1 for a company to disclose comparative information that reflects the company’s updated estimates.
ISSB Board meeting: 15 November 2022; Frankfurt

AP3B: Comparative information and updated estimates

Meeting summary

The ISSB confirmed that its requirement in proposed IFRS S1 on revising comparative information to reflect updated estimates would not apply to forward-looking estimates. It plans to provide illustrative guidance to help companies apply the requirement.

1 Proposed IFRS S1 General Requirements for Disclosure of Sustainability-related Financial Information.

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