Economists, politicians and the media watch GDP closely. But it isn't the best way to measure the health of the US economy.
Driverless cars and drones will require pinpoint location accuracy, which means our methods for measuring the Earth's centre need an overhaul.
The Australian Census has been taken since 1911. But is it still necessary in today's world of mass digital data collection?
For a long time the way we measure what is going on in our economy and society has distorted our actions. We're now building a more holistic way of measuring progress.
If you're into business and finance there are myriad numbers you can look at. But PMI is one of the better ones if you really want to know where an economy is going.
It's really hard to measure snowfall accurately. The National Weather Service relies on more than 8,000 volunteers with rulers.