The Commerce Department will release its first estimate of U.S. gross domestic product for the second quarter of 2013 on Wednesday, and economists forecast economic growth to increase at a 1 percent annualized rate for the April to June period, down from the 1.8 annual rate recorded in the first quarter, according to the median forecast in a Bloomberg survey.

The procedure for calculating GDP in the U.S. is also being revamped, as the U.S. Bureau of Economic Analysis will now include spending on research and development expenses and some forms of entertainment, which would be classified as investments. The U.S. will become the first country to adopt the new standard of calculating GDP, and government statisticians predict the economy will be measured as growing 3 percent as a result of the changes beginning July 31. 

Also this week, the Federal Open Market Committee began its two-day policy meeting Tuesday, and is expected to release a statement at 2 p.m. Eastern on Wednesday. Wall Street has been on edge for months, waiting to hear if the Federal Reserve will reveal when it will begin to taper its $85 billion-a-month asset-purchasing program.

Global stocks turned volatile in late May when Fed Chairman Ben Bernanke said the central bank planned to taper its stimulus program once the U.S. economy saw improvement. Since there are no scheduled press conferences after the announcement, economists are looking to the September meeting as the likely date for the Fed to announce scaling back its quantitative easing program.

Here Joseph Greco, managing director with brokerage firm Meridian Equity Partners Inc., gives a preview to the International Business Times on what to expect for the initial estimate of second-quarter U.S. GDP, and what the new revision means for U.S. economic growth.