Wage stagnation in the US: more than meets the eye

If you can, always look below the surface of data.

Via the Economist journalist Daniel Knowles comes a good example of why its important to look below the surface of statistics. American economist Steve Landsburg addresses a commonly heard refrain – that the wage of the median worker has barely risen in the past thirty years – and shows that all is not as it seems.

Landsburg cites a book by economist Edward Conard (first chapter, containing what we're talking about, here), which itself cites the Census Bureau. I confess that, without a more specific citation, I can't find the exact data Conard uses, but have found similar enough data (pdf, table A-5) to confirm the overall thrust of the argument.

Conard shows that from 1980 to 2005, median income in the US rose just 3 per cent once inflation is taken into account, from $25,000 to $25,700. 2005 is pre-crash, as well, so this isn't a tale of the recession.

But when you break the data down by race and gender, a very different story appears:

  1980 Median 2005 Median Increase
All Workers 25,000 25,700 3%
White Men 30,700 35,200 15%
Nonwhite Men 19,300 22,300 16%
White Women 11,200 19,600 75%
Nonwhite Women 10,200 16,500 62%

For every single demographic group, there was a much bigger increase in the median wage than we see when the groups are combined. The reason for this is obvious when it's pointed out: demographic change in the US means that there are far more (low-salaried) women and people of colour working now than there were in 2005, which pushes the overall average down.

Landsburg illustrates it with a farmyard analogy:

Imagine a farmer with a few 100-pound goats and a bunch of 1000-pound cows. His median animal weighs 1000 pounds. A few years later, he’s acquired a whole lot more goats, all of which have grown to 200 pounds, while his cows have all grown to 2000. Now his median animal weighs 200 pounds.

A very silly person could point out to this farmer that his median animal seems to be a lot scrawnier these days. The farmer might well reply that both his goats and his cows seem to be doing just fine, at least relative to where they were.

This is almost an example of Simpson's Paradox, a well-known (to stats nerds) effect where the direction of a correlation disappears when that correlation is disaggregated. I was taught it with an example involving racial discrepancies in application of the death penalty:

Sixty per cent of white murderers are executed for their crimes, and fifty per cent of black murderers. Are black people discriminated against in the application of the death penalty?

Now suppose that we break down the murder victims by race as well. We find the common pattern that people tend to attack victims of their own race:

Number of murders where death penalty is applied

White Murderer Black Murderer
White Victim 50/70=71% 25/30=83%
Black Victim 10/30=33% 25/70=36%

What about now? Does it begin to look like black people are discriminated against? In this example, black people are more likely to be executed for the murder of black or white victims; but because the murder of black victims isn't taken as seriously by the courts, the fact that murderers predominantly attack people of their race makes it look like black people are less likely to be executed than white people.

The median income example isn't quite a case of Simpson's Paradox, because there is still a positive increase in wage whether or not the statistics are disaggregated. But it's still an example of a time when it is best to dig beneath the surface.

But there is more to be said on the story of wage stagnation. Because a second claim normally accompanies the belief that US wages have stagnated, and that is that there has been a "decoupling" of wages. Due to rising inequality, the median household wage hasn't risen as fast as the mean wage:

If we've seen that the median wage grows faster when disaggregated, then the solid red line is likely to take a steeper ascent. But what happens to the dashed red line when disaggregated?

Sadly, I cannot find the data required to answer the question. If anyone knows where to look, tell me, and maybe we can put the issue to rest.

An immigrant worker protests in Orlando, Florida. Photograph: Getty Images

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

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Former Irish premier John Bruton on Brexit: "Britain should pay for our border checks"

The former Taoiseach says Brexit has been interpreted as "a profoundly unfriendly act"

At Kapıkule, on the Turkish border with Bulgaria, the queue of lorries awaiting clearance to enter European Union territory can extend as long as 17km. Despite Turkey’s customs union for goods with the bloc, hauliers can spend up to 30 hours clearing a series of demanding administrative hoops. This is the nightmare keeping former Irish premier John Bruton up at night. Only this time, it's the post-Brexit border between Northern Ireland and the Republic, and it's much, much worse.   

Bruton (pictured below), Taoiseach between 1994 and 1997, is an ardent pro-European and was historically so sympathetic to Britain that, while in office, he was pilloried as "John Unionist" by his rivals. But he believes, should she continue her push for a hard Brexit, that Theresa May's promise for a “seamless, frictionless border” is unattainable. 

"A good example of the sort of thing that might arise is what’s happening on the Turkish-Bulgarian border," the former leader of Ireland's centre-right Fine Gael party told me. “The situation would be more severe in Ireland, because the UK proposes to leave the customs union as well."

The outlook for Ireland looks grim – and a world away from the dynamism of the Celtic Tiger days Bruton’s coalition government helped usher in. “There will be all sorts of problems," he said. "Separate permits for truck drivers operating across two jurisdictions, people having to pay for the right to use foreign roads, and a whole range of other issues.” 

Last week, an anti-Brexit protest on the border in Killeen, County Louth, saw mock customs checks bring traffic to a near standstill. But, so far, the discussion around what the future looks like for the 260 border crossings has focused predominantly on its potential effects on Ulster’s fragile peace. Last week Bruton’s successor as Taoiseach, Bertie Ahern, warned “any sort of physical border” would be “bad for the peace process”. 

Bruton does not disagree, and is concerned by what the UK’s withdrawal from the European Convention on Human Rights might mean for the Good Friday Agreement. But he believes the preoccupation with the legacy of violence has distracted British policymakers from the potentially devastating economic impact of Brexit. “I don’t believe that any serious thought was given to the wider impact on the economy of the two islands as a whole," he said. 

The collapse in the pound has already hit Irish exporters, for whom British sales are worth £15bn. Businesses that work across the border could yet face the crippling expense of duplicating their operations after the UK leaves the customs union and single market. This, he says, will “radically disturb” Ireland’s agriculture and food-processing industries – 55 per cent of whose products are sold to the UK. A transitional deal will "anaesthetise" people to the real impact, he says, but when it comes, it will be a more seismic change than many in London are expecting. He even believes it would be “logical” for the UK to cover the Irish government’s costs as it builds new infrastructure and employs new customs officials to deal with the new reality.

Despite his past support for Britain, the government's push for a hard Brexit has clearly tested Bruton's patience. “We’re attempting to unravel more than 40 years of joint work, joint rule-making, to create the largest multinational market in the world," he said. It is not just Bruton who is frustrated. The British decision to "tear that up", he said, "is regarded, particularly by people in Ireland, as a profoundly unfriendly act towards neighbours".

Nor does he think Leave campaigners, among them the former Northern Ireland secretary Theresa Villiers, gave due attention to the issue during the campaign. “The assurances that were given were of the nature of: ‘Well, it’ll be alright on the night!’," he said. "As if the Brexit advocates were in a position to give any assurances on that point.” 

Indeed, some of the more blimpish elements of the British right believe Ireland, wedded to its low corporate tax rates and east-west trade, would sooner follow its neighbour out of the EU than endure the disruption. Recent polling shows they are likely mistaken: some 80 per cent of Irish voters say they would vote to remain in an EU referendum.

Irexit remains a fringe cause and Bruton believes, post-Brexit, Dublin will have no choice but to align itself more closely with the EU27. “The UK is walking away,” he said. “This shift has been imposed upon us by our neighbour. Ireland will have to do the best it can: any EU without Britain is a more difficult EU for Ireland.” 

May, he says, has exacerbated those difficulties. Her appointment of her ally James Brokenshire as secretary of state for Northern Ireland was interpreted as a sign she understood the role’s strategic importance. But Bruton doubts Ireland has figured much in her biggest decisions on Brexit: “I don’t think serious thought was given to this before her conference speech, which insisted on immigration controls and on no jurisdiction for the European Court of Justice. Those two decisions essentially removed the possibility for Ireland and Britain to work together as part of the EEA or customs union – and were not even necessitated by the referendum decision.”

There are several avenues for Britain if it wants to avert the “voluntary injury” it looks set to inflict to Ireland’s economy and its own. One, which Bruton concedes is unlikely, is staying in the single market. He dismisses as “fanciful” the suggestions that Northern Ireland alone could negotiate European Economic Area membership, while a poll on Irish reunification is "only marginally" more likely. 

The other is a variation on the Remoaners’ favourite - a second referendum should Britain look set to crash out on World Trade Organisation terms without a satisfactory deal. “I don’t think a second referendum is going to be accepted by anybody at this stage. It is going to take a number of years,” he said. “I would like to see the negotiation proceed and for the European Union to keep the option of UK membership on 2015 terms on the table. It would be the best available alternative to an agreed outcome.” 

As things stand, however, Bruton is unambiguous. Brexit means the Northern Irish border will change for the worse. “That’s just inherent in the decision the UK electorate was invited to take, and took – or rather, the UK government took in interpreting the referendum.”