AMERICAN companies are more profitable than ever — and more profitable than we thought they were before the government revised the national income accounts last week. Wage earners are making less than we thought, in part because the government now thinks it was overestimating the amount of income not reported by taxpayers.

The major change in the latest comprehensive revision of the national income and product accounts — known as NIPA to statistics aficionados — is to treat research and development spending as an investment, similar to the way the purchase of a new machine tool would be treated by a manufacturer, rather than as an expense. That investment is then written down over a number of years.

The result is to make the size of the economy, the gross domestic product, look bigger, and to appear to be growing faster, in years when new research spending is greater than the amount being written down from previous years. For the same reason, corporate profits also look better in those years.

A lot of money is spent on research and development. Nicole Mayerhauser, the chief of the national income and wealth division of the Bureau of Economic Analysis, which compiles the figures, said that in 2012 the total was $418 billion, about one-third of which was spent by governments. That amounted to about 2.6 percent of G.D.P.