Wednesday, December 30, 2009

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Consistency Concept in Accounting: IAS 8 Guide

Last reviewed: July 2026.

The consistency concept means applying accounting policies consistently to similar transactions and from one period to the next. Consistency supports comparability, but it does not mean a company must keep an inferior policy forever.

IAS 8 permits or requires policy changes when a new IFRS Standard applies or when the change produces more reliable and relevant information.

Consistency and comparability

Consistency is a method; comparability is the objective. Consistent policies help users compare periods and entities, but comparability also requires clear disclosure of differences and changes.

Accounting policies

Accounting policies are the principles, bases, conventions, rules and practices used in preparing financial statements. Examples include inventory cost formulas and measurement models.

When a policy must change

  • a new or amended IFRS Standard requires a change;
  • the change results in more reliable and relevant information;
  • specific transition provisions prescribe treatment.

When a policy should not change

Management should not change policies merely to improve current profit, meet a target or hide volatility. A change must be supported by financial-reporting objectives.

Retrospective application

Policy changes are generally applied retrospectively unless a Standard provides transition rules or retrospective application is impracticable. Comparative amounts and opening equity are adjusted as if the policy had always been applied.

Worked policy-change example

An entity changes an inventory cost formula because the new method provides more reliable and relevant information. The cumulative effect at the beginning of the comparative period is 40,000 CU after tax.

Opening retained earnings and comparative inventory and cost of sales are adjusted, with disclosure of the nature and amounts.

Changes in accounting estimates

Estimate changes arise from new information or developments and are recognised prospectively. Examples include useful lives, residual values and expected credit-loss assumptions.

They are not policy changes and are not automatically errors.

Policy versus estimate

QuestionPolicyEstimate
What is selected?Recognition, measurement or presentation principleMonetary amount subject to measurement uncertainty
Typical treatmentRetrospectiveProspective
ExampleCost model versus permitted alternativeUseful life revised from ten to eight years

Prior-period errors

Material prior-period errors are corrected retrospectively when practicable. Errors arise from failing to use or misusing reliable information that was available.

Do not describe an error as a change in estimate to avoid restatement.

Consistent presentation

Presentation and classification are retained from period to period unless a change provides more reliable and relevant information or a Standard requires it. Reclassify comparatives when practicable.

Consistency within an asset class

IAS 16 measurement models are applied to an entire class of PPE. Selective revaluation of only appreciated assets would undermine consistency.

See the IAS 16 revaluation guide.

Consistency in estimates

Using the same estimate forever is not consistency. Estimates must be updated when new evidence changes expected outcomes.

Consistency in management measures

IFRS 18 management-defined performance measures require transparent calculation and explanation of changes. A measure cannot be changed silently to present a better trend.

Review the financial performance reporting guide.

Material accounting policy information

Disclose material policy information, not long generic descriptions. Explain entity-specific choices and changes that users need to understand the statements.

Impracticability

Retrospective application is impracticable only under the IAS 8 criteria. Cost or inconvenience alone does not automatically justify prospective treatment.

Voluntary versus mandatory changes

A mandatory change follows the transition provisions of a new Standard. A voluntary change requires strong evidence that the new policy provides more reliable and relevant information.

Consistency across group entities

Consolidated financial statements require uniform accounting policies for similar transactions and events. Subsidiary reporting packages may need adjustments before consolidation.

Industry comparability

Two companies can apply IFRS correctly while using permitted different policies. Users need clear policy disclosures to understand why margins, assets or ratios differ.

Disclosure checklist

  • nature of the policy change;
  • reason and authority for the change;
  • transition method;
  • amount of adjustment by line item and period;
  • effect on earnings per share where applicable;
  • explanation when retrospective application is impracticable.

Governance and controls

  • maintain an approved policy manual;
  • track new IFRS requirements;
  • document policy-versus-estimate conclusions;
  • quantify comparative effects;
  • obtain audit and governance review;
  • update systems and disclosures;
  • retain change approvals.

Connection to the Conceptual Framework

Relevant and faithfully represented information may require a better policy even when consistency is reduced temporarily. Explain the change so comparability is restored.

Use the Conceptual Framework guide.

Documentation example

A policy-change paper should identify the old and new policy, authority, rationale, alternatives, comparative impact, system changes, disclosures and approvals.

Common mistakes

  • treating consistency as a ban on policy changes;
  • changing policy to manage profit;
  • applying estimate changes retrospectively;
  • calling an error an estimate change;
  • failing to restate comparatives;
  • using generic policy disclosures;
  • assuming inconvenience makes retrospective application impracticable.

Annual policy review

Review the accounting policy manual annually for new standards, business changes, inconsistent practice and disclosures that no longer describe actual methods.

Consistent documentation supports audit evidence and governance review.

Key takeaway

Consistency supports comparability, but IAS 8 allows justified improvement. Classify changes correctly, apply the required retrospective or prospective treatment and disclose the effect transparently.

Official references: IAS 8 Basis of Preparation of Financial Statements and Conceptual Framework for Financial Reporting.

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