THE REAL NUMBERS: Pali Lehohla is the former Statistician-General for Statistics South Africa
JOHANNESBURG - The book titled Calculated Risks: How to Know When Numbers Deceive You first published in 2002 is a read I would recommend, especially now.

It is a read that anticipated the world of fake news, misinformation and own facts - a world of denial.

Gerd Gigerenzer illustrates some major cases of denial, miscalculation and misinterpretation of probability, as well as the force of optical illusion - when your eyes exaggerate or underestimate the physical presence of objects or representations.

Top of these is that tobacco smoking causes lung cancer.

He illustrates how the tobacco companies went through a denial phase and when the scientific pressure mounted they went into casting doubt about the facts of science and subsequently resorted to massive media campaigns against science.

We also now see in our age scientific knowledge showing us that there is a rise in non-communicable diseases and that sugar consumption is largely responsible for this.

First hand, when we attended the South African chief executive's initiative in New York in September 2016, I witnessed how representatives of fizzy drinks were putting up arguments against a sugar tax.

They tended to be hostile and oblivious to the science of how sugar consumption creates medical problems for society.

The then-minister of finance Pravin Gordhan was at pains to hear their arguments.

Gigerenzer also goes to show how statistics can be abused, in particular calculating probability and interpreting its outcome. For instance take the case of testing for breast cancer.

Here he laments how medical doctors exaggerate the results of the scan. Say a thousand women are tested and four have a possibility of breast cancer and of the four one definitely has cancer.

Medical practitioners have tended to conclude that 25percent of mammography scans reveal cancer in women.

Instead of referring to the base population of a thousand when calculating the probability of a positive breast cancer outcome, practitioners use the four as a base, thus exaggerating the effectiveness of mammography testing and the prevalence of cancer.

In everyday life, too, there are strongly held cultural myths that certain food stuffs cannot be consumed, because they lead to prevalence of diseases.

In Lesotho, for instance, young men and women are discouraged from eating eggs, especially the yellow of an egg.

The recent outbreak of listeriosis in the country has attracted some similar denialist behaviour from Tiger Foods, even though the organisation has removed and recalled the named listeriosis associated products from its shelves.

As I read Gigerenzer, I cannot help but recall an intense discourse among three elderly ladies with whom my wife and I took a drive.

It was in the early 2000s, when we attended the funeral of one of Mamelodi’s famous sons, an official in the Mamelodi Sundowns squad.

The Lekala family is an anchor family in Mamelodi and a school is also named after the teacher, through whose hands many went Mamelodi sons and daughters.

As we left for the cemetery that early morning we had the benefit of giving the three elderly ladies a lift to the Eersterust cemetery, a coloured area.

They were impressed by the long procession of cars as they snaked through Eersterust towards the cemetery.

They looked at the community, people who had just woken up and were standing in front of their houses - a routine I suppose they go through daily.

They made a meal of it, saying “look at these white people, they are jealous, because we have this long procession and we are driving very good cars.

"In fact, they are jealous in the way we govern our funerals. Their funerals are always very small and not as dignified as ours.”

But as the discussion went on they argued among themselves: “But we black people die a lot, you know. We are always at funerals, especially these days.”

As they deliberated the intensity of death, they landed on what they thought the cause of deaths was, and said what you eat should contribute significantly to what kills you.

“Just think about the refrigerated chicken we buy from supermarkets. Where have you ever seen chicken with such black bones? They sell it to us deliberately to decimate our numbers.”

By that time we had arrived at the cemetery and the evolving story had to come to an end. The views represented the height of conjecture, anecdote and idle discourse.

It did not make any reference to commonly agreed-upon notions, including those of race in South Africa.

First, the community through which we drove was not white, but coloured.

Second, it is practically improbable to come to the conclusion that this community could act in unison with jealousy.

Third, the cause of death was highly speculative.

But on all the three issues the old ladies reached consensus on the truthfulness of their arguments.

I was not one to let facts get in the way of a good story - especially one involving the world view of senior citizens.

On April 3 a book titled Factfulness, by the late Professor Hans Rosling, his son Ola and Anna, Ola's wife, will be launched in Stockholm, London and New York posthumously in honour of Hans Rosling, the founder of Gapminder Foundation.

Bill and Melinda Gates gave a glowing review of the book. In his preview tweet on Twitter, Ola says among many topics that the book tackles is how the human brain works and why it fails to absorb or has an inclination to avoid facts.

Dr Pali Lehohla is the former statistician-general of South Africa and former head of Statistics South Africa.

The views expressed here are not necessarily those of Independent Media.