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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Theresa May’s stage-managed election campaign keeps the public at bay

Jeremy Corbyn’s approach may be chaotic, but at least it’s more authentic.

The worst part about running an election campaign for a politician? Having to meet the general public. Those ordinary folk can be a tricky lot, with their lack of regard for being on-message, and their pesky real-life concerns.

But it looks like Theresa May has decided to avoid this inconvenience altogether during this snap general election campaign, as it turns out her visit to Leeds last night was so stage-managed that she barely had to face the public.

Accusations have been whizzing around online that at a campaign event at the Shine building in Leeds, the Prime Minister spoke to a room full of guests invited by the party, rather than local people or people who work in the building’s office space.

The Telegraph’s Chris Hope tweeted a picture of the room in which May was addressing her audience yesterday evening a little before 7pm. He pointed out that, being in Leeds, she was in “Labour territory”:

But a few locals who spied this picture online claimed that the audience did not look like who you’d expect to see congregated at Shine – a grade II-listed Victorian school that has been renovated into a community project housing office space and meeting rooms.

“Ask why she didn’t meet any of the people at the business who work in that beautiful building. Everyone there was an invite-only Tory,” tweeted Rik Kendell, a Leeds-based developer and designer who says he works in the Shine building. “She didn’t arrive until we’d all left for the day. Everyone in the building past 6pm was invite-only . . . They seemed to seek out the most clinical corner for their PR photos. Such a beautiful building to work in.”

Other tweeters also found the snapshot jarring:

Shine’s founders have pointed out that they didn’t host or invite Theresa May – rather the party hired out the space for a private event: “All visitors pay for meeting space in Shine and we do not seek out, bid for, or otherwise host any political parties,” wrote managing director Dawn O'Keefe. The guestlist was not down to Shine, but to the Tory party.

The audience consisted of journalists and around 150 Tory activists, according to the Guardian. This was instead of employees from the 16 offices housed in the building. I have asked the Conservative Party for clarification of who was in the audience and whether it was invite-only and am awaiting its response.

Jeremy Corbyn accused May of “hiding from the public”, and local Labour MP Richard Burgon commented that, “like a medieval monarch, she simply briefly relocated her travelling court of admirers to town and then moved on without so much as a nod to the people she considers to be her lowly subjects”.

But it doesn’t look like the Tories’ painstaking stage-management is a fool-proof plan. Having uniform audiences of the party faithful on the campaign trail seems to be confusing the Prime Minister somewhat. During a visit to a (rather sparsely populated) factory in Clay Cross, Derbyshire, yesterday, she appeared to forget where exactly on the campaign trail she was:

The management of Corbyn’s campaign has also resulted in gaffes – but for opposite reasons. A slightly more chaotic approach has led to him facing the wrong way, with his back to the cameras.

Corbyn’s blunder is born out of his instinct to address the crowd rather than the cameras – May’s problem is the other way round. Both, however, seem far more comfortable talking to the party faithful, even if they are venturing out of safe seat territory.

Anoosh Chakelian is senior writer at the New Statesman.

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