Chavez's cancer claims

Summary

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Podcast Summary: More or Less — “Chavez’s Cancer Claims”

Date: January 14, 2012
Host: Tim Harford (BBC Radio 4)
Main Guests: Dr. Eduardo Cazap, Charlotte MacDonald, Dr. John Luanda, Robert Guest

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Overview

This episode of More or Less tackles two widely reported, but questionable, statistical claims from the world of politics and health. First, host Tim Harford investigates President Hugo Chavez’s suggestion that the unusual frequency of cancer diagnoses among left-wing South American leaders defies probability, with a side hinting at sinister conspiracy theories. Second, the show examines the oft-repeated “fact” that there are more doctors from Malawi in Manchester, UK, than in Malawi itself—a figure often deployed to highlight the problem of “brain drain” from developing countries.

Tone throughout is inquisitive, skeptical, and gently humorous, with an emphasis on breaking down complex statistics into plain English.

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1. Chavez’s Cancer Claims

Main Points

• The Claim
  President Hugo Chavez speculated that the US could have developed secret technology to give cancer to left-wing Latin American leaders. He based this on several leaders—including himself—being diagnosed with cancer in a short period.

  “Even using the law of probabilities, it is very difficult to explain.” (Chavez, quoted at [01:00])

• Statistical Assessment
  Tim Harford interviews Dr. Eduardo Cazap (President, Union for International Cancer Control) to probe the logic behind Chavez’s suspicions.

  • Cancer Prevalence

    “Cancer is a very frequent disease. In a given moment, close to 1% of the population has the disease.” (Dr. Cazap, [01:33])

  • Leadership Age Factor
    Leaders tend to be in higher age brackets, increasing their baseline risk.

    “Cancer is a disease of the elderly... the risk for cancer in that specific group of people is much higher.” (Dr. Cazap, [02:41])

  • Adjustment for Time
    The “cluster” occurred over several years, and with 24 Latin American countries and four affected leaders, the ratio (~1 in 6) is not especially surprising.

    “So one in five is not an unexpected number.” (Dr. Cazap, [03:21])

• Conspiracy Theory Debunked When pressed about the likelihood of the CIA “deploying a secret weapon,” Dr. Cazap responds:

  “This is a very imaginative version from Mr. Chavez, difficult to apply to the reality.” (Dr. Cazap, [03:46])

Notable Quotes

• Harford (about politicians and statistics):

  “Politicians and the media love big, bold, striking facts and statistics, but here on More Or Less, we’re a suspicious bunch.” ([03:54])

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2. The Myth of Malawian Doctors in Manchester

Main Points

• The Claim
  It is frequently stated—sometimes by the BBC itself—that “There are more doctors from Malawi in the British city of Manchester than there are in the whole of Malawi.”

  “It’s been stated many times by many people and the BBC have repeated the claim too.” (Charlotte MacDonald, [04:28])

• Fact-Checking the Numbers

  • Doctors in Malawi:
    618 registered doctors (many volunteers); only about 265 indigenous Malawian doctors. (Charlotte MacDonald, [04:38])
    • One doctor per 40,000 people in Malawi ([05:01]).
  • Doctors from Malawi in Manchester:

    “Seven.” (Charlotte MacDonald, [05:30])

  • In the UK overall:
    34 doctors from Malawi officially registered, but the real number may be slightly higher as not all declare their nationality.

• Origins of the Myth Dr. John Luanda, a Malawian physician and social historian, traces the possible roots to:

  • A 1970s scholarship arrangement, bringing a cluster of Malawian students to Manchester.
  • An especially large meeting of Malawian doctors and students in Manchester in 1981, which may have fueled perceptions back home.

    “When they reported back home, somebody from that delegation would have said, oh, we saw more doctors in Manchester than are in Malawi.” (Dr. Luanda, [07:00])

• The Truth Over Time In the 1980s, this claim was nearly true for the UK as a whole (21 doctors in Malawi, 19 in the UK). Now, conditions have changed.

• Medical Education in Malawi Today

  • Malawi’s first medical school opened in 1991. Of the 250 graduates (1991–2007), two-fifths had left Malawi, mostly for better opportunities in other African countries. ([07:31])

Notable Quotes

• Charlotte MacDonald:

  “Charlotte MacDonald with a zombie statistic. Something that just never lies down and dies.” ([07:55])

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3. Is the “Brain Drain” Always Bad?

Main Points

• Received Wisdom:
  The migration of skilled professionals from developing to developed countries (“brain drain”) is seen as a negative force.

• Counterpoint from Migration Economist Robert Guest (The Economist, author of “Borderless Economics”) offers a contrarian view:

  “The brain drain is actually good for poor countries... the prospect of earning big bucks overseas through migration causes more people than you’d expect to make the effort to acquire marketable skills. And then once they’ve acquired these skills, many of them don’t actually migrate.” ([08:23])

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Key Timestamps

| Topic | Timestamp | |------------------------------------------------|--------------| | Chavez’s Suspicion—Cancer Conspiracies | 01:00 | | Dr. Cazap on Cancer Prevalence | 01:33 | | Explanation by Age and Timeframe | 02:41 | | Debunking CIA Cancer Weapon | 03:46 | | Malawi Doctors in Manchester Fact-Check Begins | 04:21 | | Malawi Doctor Numbers—Reality | 04:38 | | Charlotte Finds the Real Figure | 05:30 | | Dr. Luanda on Myth Origins | 06:08 | | Zombie Statistic Mentioned | 07:55 | | Robert Guest on Brain Drain Benefits | 08:23 |

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Memorable Moments & Quotes

• On Politicians and Bold Stats:

  “When we come across something that sounds extraordinary, we can't help but have a dig around to see if it's really true.” (Tim Harford, [03:54])

• On Creating ‘Zombie Facts’:

  “Something that just never lies down and dies.” (Charlotte MacDonald, [07:55])

• On the Brain Drain:

  "The brain drain is actually good for poor countries... the prospect of earning big bucks overseas... causes more people... to acquire marketable skills.” (Robert Guest, [08:23])

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Summary & Conclusion

This episode of More or Less demonstrates the vital importance of healthy skepticism toward striking statistical claims, whether they originate from global leaders or are endlessly repeated in the media. The cancer “cluster” among left-wing Latin American presidents falls well within expectations once adjusted for age and timeframe, dismantling speculative conspiracy theories. Similarly, the enduring claim about Malawian doctors in Manchester is decisively debunked: not only is it untrue, but its persistence says much about the seductive power of “zombie statistics.” Finally, listeners are challenged to rethink their assumptions about the migration of skilled workers, as some economists now see “brain drain” as a potential driver of talent development back home.

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Transcript

[A]

You're listening to a download from the BBC. This is More or Less we make an edition of the programme for BBC Radio 4, but this is a download of a special edition broadcast on the World Service. Hello and welcome to More or Less on the BBC World Service. We're your weekly guide to the numbers in the news and in life. And I'm Tim Harford. If you spot a statistic that you'd like us to investigate or which just doesn't make sense to you, please email us at more or lessbc.co.uk listeners, Lucy, Miguel, Peter and John have done just that, asking us to check out a statistical statement made by President Hugo Chavez of Venezuela. He's been questioning whether the United States has developed a secret technology to give cancer to left wing leaders in Latin America. President Chavez was treated for cancer last year and here he is speaking the day after the Argentinian President Cristina Fernandez was diagnosed with the condition Bueno dificilito.

[B]

No.

[C]

Even using the law of probabilities, it is very difficult to explain.

[A]

Paraguay's president and Brazil's current and previous president have also been treated for cancer, which meant five in total at the time President Chavez was speaking, although it has now emerged that President Fernandez of Argentina had been misdiagnosed. But was President Chavez right that such a concentration of cancer does defy probability? I asked Dr. Eduardo from Argentina, who's president of the Union for International Cancer Control.

[B]

One important concept is to note that cancer is a very frequent disease. In a given moment, close to 1% of the population has the disease.

[A]

Still there are, I think, 24 Latin American countries.

[B]

Yes. If we now consider President Chavez in Venezuela with the disease, the diagnosis of pelvic sarcoma, and President Lugo from Paraguay with a lymphoma, the President of Brazil, also with a lymphoma, and now the past President of Brazil, Mr. Lula, is now under treatment for laryngeal carcinoma. So that means that 4 over 24, it sounds pretty reasonable as an average risk for the population.

[A]

And is this because of the age of the leaders involved? Because it seems quite high. This is one in six. And you said, well, 1%, 2% of the population get cancer at any one time.

[B]

Yes, well, cancer is a disease of the elderly. So one point that corrects that 1% is the fact that the slot between 50 to 80 years, the proportion, the risk for cancer in that specific group of people is much higher. The second issue to be considered is the fact that we are not considering an annual estimation because the presentation of cancers in these leaders was along two, three or four years. So if we make a specific adjustment for the age group of the population and then you multiply for, we must say, three or four years. So one in five is not an expected number.

[A]

One final question. Do you think the CIA is going to deploy this secret weapon? Again,

[B]

I think that this is a very imaginative version from Mr. Chavez, difficult to apply to the reality.

[A]

Thank you very much and thanks for your patience with the last question. Dr. Eduardo Casap. Politicians and the media love big, bold, striking facts and statistics, but here on More Or Less, we're a suspicious bunch. And when we come across something that sounds extraordinary, we can't help but have a dig around to see if it's really true. Which is why this often quoted fact caught our attention.

[D]

There are more doctors from Malawi in the British city of Manchester than there are in the whole of Malawi.

[A]

It's been stated many times by many People and the BBC have repeated the claim too. Well, Charlotte MacDonald has been testing the truth of it. Charlotte?

[D]

OK, so first off, how many doctors are there in Malawi? The Medical Council of Malawi told me they have 618 registered doctors, but a good number of these will be volunteers from overseas. A recent estimate of the number of Malawian doctors came up with a figure of 265.

[A]

Sounds amazingly small for a country with a population of 15 million people.

[D]

Well, yes, Tim, the World Health Organization says there is one doctor for every 40,000 people in Malawi. That compares to roughly one for every 3,000 in Nigeria and one for every 400 people in the UK.

[A]

OK, so not a lot of doctors. How many doctors from Malawi are in Manchester?

[D]

Well, there's no official list, so I rang around every hospital and every health authority in the Greater Manchester area.

[A]

Oh, you're good.

[D]

Thanks, Tim. And I found.

[A]

Don't tease us, Charlotte. How many?

[D]

Seven.

[A]

Seven.

[D]

Seven.

[A]

That's a long way off. 265.

[D]

Yes. And across the UK as a whole, we know there are only 34 doctors registered as being from Malawi, but doctors don't have to give their nationality when they register, so there will be more. Still, no hard numbers suggest there are anywhere near as many doctors from Malawi and Manchester as there are in Malawi.

[A]

Ok, so where does this false fact come from?

[D]

I couldn't trace it back to who said it first, but I've been speaking to a Malawian doctor and social historian called John Luanda, who came to study medicine in the UK in the 1970s because there were no medical schools in Malawi then.

[E]

The reason for this myth is very difficult to fathom but you know, there are several possibilities. In 1970 there was an agreement between Manchester University and the government of Malawi to allow bright students who had completed two years of their BSc degree to come to Manchester to study medicine. So Manchester became one of the most common universities that accepted Malawians. The other reason was that towards the end of the 70s the government was anxious for Malawian doctors to return home. In 1981 the Minister of Health in Malawi really made a last ditch attempt to get their students and doctors to come back home and we had a big meeting in Manchester. Students, qualified doctors were invited to come and attend and I can imagine probably when they reported back home somebody from that delegation would have said, oh, we saw more doctors in Manchester than are in Malawi.

[A]

But it is well and truly false then.

[D]

Yes, as regards Manchester. But interestingly this was almost true about the UK as a whole in the 1980s. John Lawanda reckons that in 1985 there were 21 indigenous doctors in Malawi and 19 Malawian doctors in the UK.

[A]

So what's the situation with medical students in Malawi now?

[D]

The country got its first Medical School in 1991. A study found that about 250 students had graduated between then and 2007, two fifths of whom had left Malawi. Now they won't have all gone to Manchester or even the UK as immigration rules have changed. Popular destinations are African countries such as Botswana and Lesotho where there are no medical schools and wages are higher.

[A]

Thanks Charlotte. Charlotte MacDonald with a zombie statistic. Something that just never lies down and dies. Now the non fact about Malawian doctors has sometimes been used by people expressing concern that too many skilled workers have been enticed abroad to work in wealthier countries. And clearly such a brain drain is a huge problem for developing countries in general. Or is it? Robert Guest, business editor at the Economist and author of Borderless Economics, argues not.

[C]

It's one of the most surprising facts of modern economics that the brain drain is actually good for poor countries. Now we all know that it's good for the migrants themselves, but what's more surprising, it's actually good for the places they leave as well. The interesting thing is that the prospect of earning big bucks overseas through migration causes more people than you would expect to make the extra effort to acquire marketable skills. And then once they've acquired these skills, many of them don't actually migrate.

[A]

Robert Guest and that's all we've got time for this week. Do please send us your questions and comments to more or lessbc.co.uk. and you can download our podcast via our website, bbcworldservice.com more or less More or Less was presented by me, Tim Harford of the Financial Times. The producer was Ruth Alexander.