An accounting concept that calls for establishing a level of conformity in all accounting treatment, methods, policies and procedures across different accounting periods for the sake of a better comparability and undesirability of the underlying events and transactions over the course of successive accounting periods. Examples about cases where selection of accounting methods (as reflected in the measurement of value) comes into play include valuation of inventory (LIFO, FIFO, etc.), depreciation of fixed assets, provisioning, etc.

Notwithstanding the requirements of this principle, accounting concepts and principles should be dynamic over time to keep pace with best practices and emerging trends and developments in the profession and the market.

Consistency comes in different senses: vertical consistency, horizontal consistency, and third dimensional consistency.