U.S. economy set to grow 3% - due to accounting change. The U.S. economy will become 3% larger in July as the government becomes one of the first to use a new international standard for GDP accounting. Among other things, statisticians will now take into account R&D investment, which will add just over 2%, and creative works, which will add another 0.5%. The government will backdate the alterations to 1929, so there are unlikely to be changes in trends or cycles.