How the US economy is being recalculated

The way the US economy is measured has changed, to include the amount spent on intellectual property outlays such as pop song production and drug patents for the first time.

"GDP is probably the single most important statistic affecting businesses, households, and governments," says Steve Landefeld, director of the Bureau of Economic Analysis (BEA), which measures gross domestic product - the total amount of goods and services produced in the US economy during a given quarter.

Calculating GDP, he says, is incredibly difficult, because "it's a continually changing economy that we're chasing".

Now, in what the BEA says is the biggest change in the calculations since 1999, the way that US economic activity is reported has been updated.

The goal is to finally include something many have already noticed: the shift away from the production economy of factories and farms towards the knowledge economy - the investment and economic production in intellectual property, which includes everything from the amount spent on writing a hit TV show to researching a cancer cure.