What does a latte tell us about currencies? Very little, actually

Purchasing power parity is not the same as the Big Mac Index.

The Wall Street Journal sees what the Economist is having, and it likes it. The latter's Big Mac Index is famous for demonstrating the variation in prices for the same good around the world. Despite Big Macs being basically identical no matter where you are, the dollar price varies wildly, from $6.81 in Switzerland down to just $1.82 in India. It's so influential that it's widely thought that Argentina is exerting pressure on its branches of McDonalds to keep the price down so as to not provide evidence of the nation's tinkering with reported inflation.

So now the WSJ wants a piece of the action, and has created its Starbucks Latte Index. I mean, it doesn't call it that, but that's what they're thinking:

Click to embiggen.

But like the Economist, the WSJ draws the wrong inferences from the variation. They both have a habit of using the data to illustrate purchasing power parity, the idea that some currencies are under- or over-valued because a comparable basket of goods varies in price. So the WSJ's Ira Iosebashvili writes:

One way to determine how currencies stack up is purchasing-power parity, or PPP, which compares the amount of currency needed to buy the same item in different countries. A grande latte at Starbucks, for example, costs $4.30 in New York, but the equivalent of $9.83 using Norwegian krone in Oslo, and just $3.92 in Turkish lira in Istanbul.

Starbucks Lattes and Big Macs both have another unique feature, though, which renders them less useful for comparing the strength of a currency overall: they are both made up of highly fungible goods, produced in two of the most integrated supply chains in the world. McDonalds, for instance, doesn't need to buy artisanal wheat from an individual farm; it can just trade in "wheat" as a mass-produced, internationally-traded com oddity. The company has even invented a product to sell to take advantage of variations in the cost of pork, the McRib.

In fact, for Starbucks, that's even more true than it is for MacDonalds. While Maccy D's has made a big deal out of its promise to only use British beef in its British burgers, most of the countries Starbucks operates in in don't grow their own coffee. That has to be imported from South America or North Africa, and so a Starbucks in London will almost certainly be paying the same for its coffee as a branch in Oslo, despite the difference in retail price being over $6.

What the Starbucks and Big Mac indices actually show is the price of unskilled labour and retail space. Those are the parts of the companies' businesses which, no matter how hard they try, they can't erase national differences from. Operating in Oslo, land of high taxes, is always going to be expensive, no matter how strong or weak the krone is.

The Starbucks index even makes this clear, thanks to the fact that the WSJ has included three American cities. A latte in New York City costs more than one in Detroit, a difference that self-evidently can't be due to the currency variation.

But the really important news is that London is actually one of the cheapest cities in the world for a Starbucks latte. Still overpriced for what it is, though.

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Show Hide image

Geoffrey Howe dies, aged 88

Howe was Margaret Thatcher's longest serving Cabinet minister – and the man credited with precipitating her downfall.

The former Conservative chancellor Lord Howe, a key figure in the Thatcher government, has died of a suspected heart attack, his family has said. He was 88.

Geoffrey Howe was the longest-serving member of Margaret Thatcher's Cabinet, playing a key role in both her government and her downfall. Born in Port Talbot in 1926, he began his career as a lawyer, and was first elected to parliament in 1964, but lost his seat just 18 months later.

Returning as MP for Reigate in the Conservative election victory of 1970, he served in the government of Edward Heath, first as Solicitor General for England & Wales, then as a Minister of State for Trade. When Margaret Thatcher became opposition leader in 1975, she named Howe as her shadow chancellor.

He retained this brief when the party returned to government in 1979. In the controversial budget of 1981, he outlined a radical monetarist programme, abandoning then-mainstream economic thinking by attempting to rapidly tackle the deficit at a time of recession and unemployment. Following the 1983 election, he was appointed as foreign secretary, in which post he negotiated the return of Hong Kong to China.

In 1989, Thatcher demoted Howe to the position of leader of the house and deputy prime minister. And on 1 November 1990, following disagreements over Britain's relationship with Europe, he resigned from the Cabinet altogether. 

Twelve days later, in a powerful speech explaining his resignation, he attacked the prime minister's attitude to Brussels, and called on his former colleagues to "consider their own response to the tragic conflict of loyalties with which I have myself wrestled for perhaps too long".

Labour Chancellor Denis Healey once described an attack from Howe as "like being savaged by a dead sheep" - but his resignation speech is widely credited for triggering the process that led to Thatcher's downfall. Nine days later, her premiership was over.

Howe retired from the Commons in 1992, and was made a life peer as Baron Howe of Aberavon. He later said that his resignation speech "was not intended as a challenge, it was intended as a way of summarising the importance of Europe". 

Nonetheless, he added: "I am sure that, without [Thatcher's] resignation, we would not have won the 1992 election... If there had been a Labour government from 1992 onwards, New Labour would never have been born."

Jonn Elledge is the editor of the New Statesman's sister site CityMetric. He is on Twitter, far too much, as @JonnElledge.