Accounting principles are the rules that an organization follows when reporting financial information. A number of basic accounting principles have been developed through common usage.
The Financial Accounting Standards Board (FASB) is an independent, nonprofit organization that sets the standards for financial accounting and reporting standards for both public- and private-sector businesses in the United States, including generally accepted accounting principles (GAAP).
Accrual principle. This is the concept that accounting transactions should be recorded in the accounting periods when they actually occur, rather than in the periods when there are cash flows associated with them. This is the foundation of the accrual basis of accounting. It is important for the construction of financial statements that show what actually happened in an accounting period, rather than being artificially delayed or accelerated by the associated cash flows. For example, if you ignored the accrual principle, you would record an expense only when you paid for it, which might incorporate a lengthy delay caused by the payment terms for the associated supplier invoice.