Our understanding of the world is often shaped by geographical maps. But this tells us nothing about where in the world people live. To understand this, we need to look at population density. How does population density vary across the world?

In the past the average woman had five children. In the past fifty years, this number has halved as a result of women empowerment, declining child mortality and the rising cost of bringing up children.

Every 5th adult in the world smokes tobacco. More than one-third (35%) of men in the world do, but just over 6% of women. How do sex differences in smoking vary across the world?

One-in-five (20%) adults in the world smoke tobacco. But where in the world is smoking most common?

Living conditions are vastly unequal between different places in our world today. Today’s global inequality of opportunity means that what matters most for your living conditions is the good or bad luck of your place of birth. We look at how where you’re born is the strongest determinant of your standard of living, whether in life expectancy, income or education.

Diarrheal diseases remain one of the leading causes of deaths in children. One simple intervention – oral rehydration therapy (ORT) – has saved millions of children in recent decades. Yet it can still do more. We look at the future potential of ORT; barriers to its use; and how many lives it could potentially save.

The world has made significant progress in recent decades in reducing deaths from diarrheal diseases, particularly for children. One of the most successful interventions has been oral rehydration therapy (ORT): a simple salt, water and sugar solution. We look at what ORT is, how it was developed, and how many lives it might have saved.

Diarrheal diseases are one the largest killers of children, responsible for more than half a million child deaths in 2017. Rotavirus is the leading cause of diarrheal deaths in children. There is, however, an effective tool against it: the rotavirus vaccine. We look at rotavirus vaccine coverage across the world; the estimated number of lives saved and its potential to save more children.

Despite being treatable and preventable, 1.6 million people died from diarrheal diseases in 2017; one-third were children under five years old. This makes it one of the largest killers of children. Here we look at where and why children are dying from diarrrheal diseases, and what we can do stop this.

15,000 children under five years old die every day. To reduce this figure we need to understand what children are dying from, and what interventions are available to stop this. Here we look at the number of children dying by each cause – from pneumonia to diarrheal diseases, malaria and malnutrition. We also present the range of interventions that are available to prevent children from dying.

15,000 children under five years old die every day. If we want to save as many children as possible, we need to first understand where children are dying. Here we look at how countries compare in the number of child deaths, and how this has changed over the past few decades.

How does sex ratio at birth vary across the world? We might expect that naturally an equal number of boys and girls are born, but this is not the case. There are biological reasons why more boys than girls are born each year: around 105 boys per 100 girls. But in countries with a strong son preference, the sex ratio is even more skewed.

Vaccines have provided some of the greatest interventions to global health to date. But attitudes to vaccination – whether they are safe, effective and important – are often divisive. Here we look at results from the largest global survey to date – the Wellcome Global Monitor – on attitudes to vaccination across the world. 92% of the world thinks vaccines are important for children to have, but in some countries skepticism on their safety is as high as 1-in-3.

92% of people in the world think vaccines are important for children to have. But in some countries, skepticism about their safety is as high – in some cases every 3rd person. What effect do public attitudes have on vaccine coverage rates, and what can we do about skepticism to vaccines?

Are we happier when we spend more time with others? Studies suggest social relations are key factor in happiness & life satisfaction. We take a closer look at the evidence for how much social connections matter for happiness.

Loneliness has been reported to be as lethal as ’15 cigarettes a day’. What is the evidence for this? We take a deeper look at the data and research on the link between loneliness and health and wellbeing.

The UN projects that the world population will increase from 7.7 billion today to 10.9 billion by 2100. Most of this growth will come from Africa; its share of the world population will rise from 17% to 40%. More than 8-in-10 people will live in Asia or Africa by the end of the century.

An online data appendix explaining the data and methods used to estimate the historical poverty trends presented in Roser and Hasell (2021)

Many lecturers and teachers use Our World in Data in their teaching. This spans a range of levels from primary school to post-graduate university education. Matthew Cone, a US high-school teacher shares how he uses OWID with his pupils.

Our World in Data gets lots of feedback on how our work is used by policymakers, journalists, researchers and the public. But sometimes we get feedback from people who use us in ways we could never have imagined. Dr Jill Gordon shares her experiences on how she uses OWID in her work as a medical doctor.

South Koreans are on average 32-times richer than in 1950; Romanians 20-times; Chinese 16-times. Other countries stagnated and remained poor. We look at how incomes have changed around the world and why it matters.