The national income and product accounts (NIPA) are part of the national accounts of the United States. They are produced by the Bureau of Economic Analysis of the Department of Commerce. They are one of the main sources of data on general economic activity in the United States.
They use double-entry accounting to report the monetary value and sources of output produced in the country and the distribution of incomes that production generates. Data are available at the national and industry levels.
Seven summary accounts are published, as well as a much larger number of more specific accounts. The first summary account shows the gross domestic product (GDP) and its major components. The table summarizes national income on the left (debit, revenue) side and national product on the right (credit, expense) side of a two-column accounting report. Thus the left side gives GDP by the income method, and the right side gives GDP by the expenditure method. The GDP is given on the bottom line of both sides of the report. GDP must have the same value on both sides of the account. This is because income and expenditure are defined in a way that forces them to be equal (see accounting identity). We show the 2003 table later in this article; we present the left side first for a convenient screen display.
The U.S. report (updated quarterly) is available in several forms, including interactive, from links on the Bureau of Economic Analysis (BEA) NIPA ([1]) page. Other countries report based on their own adopted system of National accounts which are frequently based on the U.S. NIPAs, the widely adopted United Nations System of National Accounts, or their own custom approach. The level of detail (granularity) accounted for internally, and reported publicly, varies widely across countries. Likewise, a nation's system of accounts, (analogous to a firm's Chart of accounts) are typically gradually revised and updated on their own individual schedule. The U.S. NIPAs are prepared by the staff of the Directorate for National Economic Accounts within the BEA. The source data largely originates from public sources, such as government surveys and administrative data, and they are supplemented by data from private sources, such as data from trade associations (BEA 2008: 1–6).