What does the popcorn index teach us about the economy?
Thanks for asking! Figuring out how well the economy is doing might seem like the preserve of those working in big accounting firms or financial institutions dealing with complicated graphs and calculations on a daily basis.
But in reality, we're exposed to certain clues going about our everyday lives without even realising that they offer insight into our spending habits.
An interesting example to look out for is whether people are buying popcorn in your local cinema.
The theory of the popcorn index was introduced in 2009 by Rupert Gavin, then head of Odeon Cinema Group.
The Great Recession had begun the year before and was impacting people's ability to spend money on going out.
Gavin observed that weekly popcorn sales in Odeon cinemas were mirroring the ups and downs of the FTSE stock index.
The more people bought popcorn, the better the economy was doing.
And according to Gavin, at certain moments popcorn sales actually led the FTSE.
Writing for This Is Money in August 2009 he called the Odeon Popcorn Index an uncannily accurate barometer of the nation's financial prospects.
He said it also bore truth across other European countries like Germany, Spain and Italy.
Well, it's interesting to note that people didn't stop going to the cinema completely during the recession.
Indeed, Avatar, which was released in late 2009, would break box office records all over the world.
That's likely down to the reality that cinema provides a helpful form of escapism.
As Gavin put it in This Is Money, in a recession many people prefer to maximise their short -term enjoyment and to forget about the economic doom and gloom.
Still, people were more likely to think twice about spending a few extra pounds on popcorn, a snack that's certainly synonymous with a trip to the cinema, but also notoriously pricey.
Okay, the popcorn index is unlikely to replace serious economic analyses, but nevertheless it's noteworthy as a quirky indicator.
And in February 2017, BBC News revealed that there are actually a number of other similar examples in a feature with the headline, How Fast Food Reveals Secrets of the Economy.
Well, the Big Mac Index is pretty well known.
It's used to compare purchasing power in different countries based on the price of McDonald's most famous burger, the Big Mac.
Meanwhile, the Mars Bar Standard was created by Financial Times writer Nico Colchester in the 1980s after he noticed that the chocolate bar's price in the UK was neatly correlated with the buying power of Pound Sterling.
There you have it. Now you know what the popcorn index is.
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