Now they use different methods to accomplish the same thing, much as the media has.

FORBES: The Financial Transaction Tax Is Bad Business For Europe

Both RPI and CPI measure changes in prices, but track slightly different baskets of goods and services and use different methods to calculate inflation.

BBC: UK inflation rate nudged up to 2.8% by rising fuel costs

Some of Etsy's competitors use different methods to police their sites.

WSJ: Busted by the Crafts Cops

But in fact, the main reason for the two indices rising at different rates is because they use different arithmetical methods for calculating average prices.

BBC: New inflation measure proposed

There are a number of different reasonable methods one could use that would result in a variety of different estimates.

FORBES: GOP Senator Knowingly Distorts GAO Report He Commissioned To Launch Most Dishonest Attack On Obamacare To Date

Another way to determine attitudes is natural language processing methods, where software algorithms use different sets of rules to decipher statements and try to glean their intended meaning.

FORBES: Can You Measure Your Digital Eminence?

Data collection methods vary between countries - many use different age limits to define exactly who is classed a young person.

BBC: Global youth unemployment: Making sense of the numbers

Three different aid-calculating methods are in use.

FORBES: Paying for College: How the Financial Aid Formulas Work