 The term "accounting identity" may be used to distinguish between propositions that are theories (which may or may not be true, or relationships that may or may not always hold) and statements that are by definition true.Despite the fact that the statements are by definition true, the underlying figures as measured or estimated may not "add up" due to measurement error, particularly for certain identities in macroeconomics.The most basic identity in accounting is that the balance sheet must balance, that is, that assets must equal the sum of liabilities (debts) and equity (the value of the firm to the owner).