Factfulness: Ten Reasons We're Wrong About the World – and Why Things Are Better Than You Think (16 page)

In this chart, money and health go hand in hand. We don’t know from just looking at the line which comes first or what the relationship is between the two. It might be that a healthy population produces more income. It might be that a rich population can afford better health. I think both are true. What we do know from such a line is that in general where income is higher, health is better.

We can also find straight lines when we compare income levels with education, marriage age, and spending on recreation. More income goes hand in hand with longer average schooling, with women marrying later, and with a greater share of income going toward recreation.

When we compare income with basic necessities like primary-level education or vaccination, we see S-shaped curves. They are low and flat at Level 1, then they rise quickly through Level 2, because above Level 1, countries can afford primary education and vaccination (the most cost-effective health intervention there is) for just about the entire population. Just as we will buy ourselves a fridge and a cell phone as soon as we can afford them, countries will invest in primary education and vaccination as soon as they can afford them. Then the curves flatten off at Levels 3 and 4. Everyone already has these things. The curves reach their maximum and stay there.

Remembering about this kind of curve will help you to improve your guessing about the world: on Level 2, almost everyone can already afford to have their basic physical needs met.

The babies-per-woman curve looks like a slide in a playground. It starts flat, then, after a certain level of income, it slopes downward, and then it flattens out and stays quite low, just below two babies per woman.

Shifting away from income graphs for a moment, we see a similar shape for the cost of vaccinations. In basic math classes, we teach children to multiply. If an injection costs $10, what’s the price of a million injections? UNICEF knows how to count but it has also saved millions of children’s lives by not accepting a straight line. It has negotiated huge contracts with pharmaceutical companies, in which the price is cut to the bare minimum in return for guaranteed long contracts. But when you have negotiated to the bottom price, you can’t get lower. That’s another slide-shaped curve.

Your tomato plant will grow as long as it gets water. So, if more water is what it needs, why don’t you turn the hose on it, so you can grow an enormous prize-winning tomato? Of course you know that doesn’t work. It’s a question of dosage. Too little and it dies. Too much and it dies too. Tomato survival is low in very dry and very wet environments, but high in environments that are in the middle.

Similarly, there are some phenomena that are lower in countries on Level 1 and countries on Level 4, but higher in middle-income countries—which means the majority of countries.

Dental health, for example, gets worse as people move from Level 1 to Level 2, then improves again on Level 4. This is because people start to eat sweets as soon as they can afford them, but their governments cannot afford to prioritize preventive public education about tooth decay until Level 3. So poor teeth are an indicator of relative poverty on Level 4, but on Level 1 they may indicate the opposite.

Motor vehicle accidents show a similar hump-shaped pattern. Countries on Level 1 have fewer motor vehicles per person, so they do not have many motor vehicle accidents. In countries on Levels 2 and 3, the poorest people keep walking the roads while others start to travel by motor vehicles—minibuses and motorcycles—but roads, traffic regulations, and traffic education are still poor, so accidents reach a peak, before they decline again in countries on Level 4. The same goes for child drownings as a percentage of all deaths.

Like tomatoes, human beings need water to survive. But if you drink six liters at once, you will die. The same goes for sugar, fat, and medicines. Actually, everything you need to survive is lethal in high dosage. Too much stress is bad, but the right amount improves performance. Self-confidence has its optimal dosage. The intake of dramatic news from the rest of the world probably has its optimal dosage too.

Finally, doubling. The doubling pattern of the Ebola virus is actually a very common type of pattern in nature. For example, the number of
E. coli
bacteria in a body can explode in just a few days because it can double every 12 hours: 1, 2, 4, 8, 16, 32 … The world of transport also contains many doubling patterns. As people’s incomes increase, the distance they travel each year keeps doubling. So does the share of their income that they spend on transport. On Level 4, transport is behind one-third of all CO
₂
emissions—which also double with income.

Most people’s incomes grow much slower than bacteria, unfortunately. Still, even if your income increases by only 2 percent a year, after 35 years it will have doubled. And then, if you maintain 2 percent growth, in another 35 years it will have doubled again. Over 200 years—if you lived that long—it would double six times, which is exactly what we saw in Sweden’s bubble trail in the last chapter, and which is typically the slow and steady way countries have moved from Level 1 to Level 4. The graph on the next page shows how six doublings move you across all four income levels.

I have divided the levels in this way because that’s how money works. The impact of an additional dollar is not the same on different levels. On Level 1, with $1 a day, another dollar buys you that extra bucket. That is life-changing. On Level 4, with $64 a day, another dollar has almost no impact. But with another $64 a day, you could build a pool or buy a summer house. That’s life-changing for you. The world is extremely unfair, but doubling one’s income, from any starting point, is always life-changing. I use this doubling scale whenever I compare income because that’s how money works.

By the way, the scales for measuring earthquakes, sound levels, and pH works in the same way.

Curves come in many different shapes. The part of the curve with which we are familiar, living on Level 4, may not apply at all on Levels 1, 2, or 3. An apparently straight upward trend could be part of a straight line, an S-bend, a hump, or a doubling line. An apparently straight downward trend could be part of a straight line, a slide, or a hump. Any two connected points look like a straight line but when we have three points we can distinguish between a straight line (1, 2, 3) and the start of what may be a doubling line (1, 2, 4).

To understand a phenomenon, we need to make sure we understand the shape of its curve. By assuming we know how a curve continues beyond what we see, we will draw the wrong conclusions and come up with the wrong solutions. That is what I did before I realized that the Ebola epidemic was doubling. And that is what everyone is doing who thinks that the world population is
just
increasing.

Factfulness is … recognizing the assumption that a line will just continue straight,
and remembering that such lines are rare in reality.

To control the straight line instinct,
remember that curves come in different shapes.