The consistency concept requires a business to apply the same accounting policies, methods and estimates from one financial period to the next. Without consistency, it would be impossible to compare a company’s performance across years or to identify genuine trends in revenue, profitability and financial position.
This principle is embedded in FRS 102 and is one of the foundational requirements of the UK accounting standards framework. It also aligns with the Companies Act 2006, which requires that accounting policies are applied consistently within the same accounts and from one financial year to the next.
Why consistency matters
Financial statements are only useful if they allow meaningful comparison. A company that switches depreciation methods, changes revenue recognition policies or alters inventory valuation from year to year produces accounts that cannot be compared reliably.
| Without consistency | With consistency |
|---|---|
| Profit fluctuations may reflect policy changes, not real performance | Profit movements reflect genuine business activity |
| Users cannot identify trends | Trends in revenue, costs and margins are visible |
| Ratios become unreliable | Financial ratios are comparable across periods |
| Auditors face additional work verifying each change | Audit effort can focus on transactions, not policy shifts |
Consistency benefits every user of the accounts: directors, shareholders, lenders, HMRC and analysts.
What consistency covers
The consistency concept applies to every area where a business makes an accounting policy choice. The most common areas include:
Depreciation methods
A company may choose to depreciate its plant and machinery using the straight-line method (equal annual charges) or the reducing balance method (higher charges in early years, declining over time). Once chosen, the same method must be applied to that class of assets in every subsequent period.
| Method | Year 1 charge | Year 5 charge | Best for |
|---|---|---|---|
| Straight-line | Equal each year | Equal each year | Assets used evenly over time |
| Reducing balance | Higher | Lower | Assets losing value quickly early on |
Revenue recognition
If a business recognises revenue on long-term contracts using the stage of completion method, it must continue to do so. Switching between recognising revenue at a point in time and over time without justification would undermine comparability.
Inventory valuation
UK businesses typically value inventory using FIFO (first in, first out) or weighted average cost. The chosen method must be applied consistently to comparable categories of inventory.
Provisions and estimates
While the amounts of provisions and estimates will change as circumstances evolve, the basis for calculating them should remain consistent. For example, if a company calculates its warranty provision based on 2% of revenue, it should continue to use that approach unless there is evidence that the rate is no longer appropriate.
Consistency in FRS 102
FRS 102 addresses consistency in several places:
Section 10: Accounting policies
Section 10 requires an entity to select and apply accounting policies consistently for similar transactions, events and conditions. An entity should only change an accounting policy if:
- The change is required by a new or amended FRS
- The change results in financial statements providing reliable and more relevant information
When a change is made, the entity must apply it retrospectively – restating prior period comparatives as if the new policy had always been applied. This ensures that the comparative figures remain meaningful.
Disclosure requirements
When an accounting policy is changed, FRS 102 requires disclosure of:
- The nature of the change
- The reasons for the change
- The amount of the adjustment for each financial statement line item affected
- The adjustment relating to prior periods
These disclosures ensure transparency, so users understand why the numbers have changed and can assess the impact.
When can a business change its accounting policy?
Changes in accounting policy are permitted but restricted. The two acceptable reasons are:
1. Required by a new standard
When the FRC amends or replaces an accounting standard, affected entities must adopt the new requirements. For example, when the revised revenue recognition provisions of FRS 102 took effect for accounting periods beginning on or after 1 January 2026, entities had to review and, where needed, change their revenue policies to comply.
2. Voluntary change to improve relevance and reliability
A company may voluntarily change a policy if the new policy provides a more faithful representation of the entity’s transactions. For example, a property company might change from historical cost to the revaluation model for its investment properties if the directors believe revalued amounts give a more relevant view of the company’s financial position.
The change must be genuine and justifiable. A company cannot change policies simply to produce a more favourable profit figure in a particular year.
Consistency vs changes in estimates
It is important to distinguish between a change in accounting policy and a change in accounting estimate.
| Change type | Treatment | Example |
|---|---|---|
| Change in policy | Applied retrospectively (prior periods restated) | Switching depreciation method from reducing balance to straight-line |
| Change in estimate | Applied prospectively (current and future periods only) | Revising the useful life of an asset from 10 years to 8 years |
A change in estimate does not violate the consistency concept. Estimates are, by their nature, subject to revision as new information becomes available. The underlying policy (depreciation over the useful life) remains the same; only the input to the calculation has changed.
Consistency within a single set of accounts
The concept applies not only between periods but also within a single period. A company must apply the same accounting policy to all similar items. For example:
- All items of plant and machinery should be depreciated using the same method (unless sub-classes are identified and disclosed)
- All long-term construction contracts should use the same revenue recognition approach
- All categories of comparable inventory should be valued using the same method
Applying different policies to similar items within the same accounts would undermine the internal coherence of the financial statements.
Consistency and financial accounting
The consistency concept is particularly important in financial accounting because statutory accounts are the primary documents used by external stakeholders. Investors comparing a company’s performance over several years rely on the assumption that the numbers have been prepared on a like-for-like basis.
Management accounts, by contrast, may adopt different presentations or methods from period to period for internal decision-making purposes, although even here consistency improves the quality of analysis.
Consistency and audit
Auditors pay close attention to consistency. Their procedures typically include:
- Comparing accounting policies disclosed in the current year to those in the prior year
- Investigating any changes and assessing whether they are justified
- Testing the retrospective application of any policy changes to ensure comparatives are properly restated
- Reviewing estimates to distinguish genuine revisions from disguised policy changes
An unexplained or unjustified change in accounting policy is a significant audit issue that may result in a modified audit opinion.