Homicide data: how sources differ and when to use which one
There are several ways to measure homicides. What approaches do different sources take? And when is which approach best?
June 26
Article
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Our latest articles, data updates, and announcements
June 02
Article
Population momentum: if the number of children per woman is falling, why is the population still increasing?
50 years ago, the total fertility rate was five. This figure has more than halved. Yet the global population is still rising — why?
May 26
Article
How do researchers study the prevalence of mental illnesses?
Global data on mental health is essential to understand the scale and patterns of these illnesses, and how to reduce them. How do researchers collect this data, and how reliable is it?
May 26
Article
How are mental illnesses defined?
Mental illnesses are a range of conditions that significantly affect people’s lives. What are their symptoms?
April 27
Article
How is food insecurity measured?
Billions of people suffer from food insecurity. What does it mean to be food insecure?
April 18
Article
Learning curves: What does it mean for a technology to follow Wright’s Law?
Technologies that follow Wright’s Law get cheaper at a consistent rate, as the cumulative production of that technology increases.
April 11
Article
Mortality in the past: every second child died
The chances that a newborn survives childhood have increased from 50% to 96% globally. How do we know about the mortality of children in the past? And what can we learn from it for our future?
April 04
Article
How does age standardization make health metrics comparable?
Age standardization is a statistical method used to compare disease rates, or other health indicators, between populations while accounting for differences in their age structure.
March 29
Article
Artificial intelligence has advanced despite having few resources dedicated to its development — now investments have increased substantially
The available resources have increased substantially. We should expect that the field continues to advance rapidly.
March 28
Article
What is Moore's Law?
Exponential growth is at the heart of the rapid increase of computing capabilities.
March 18
Article
Two centuries of rapid global population growth will come to an end
Global population has increased rapidly over the past century. This period of rapid growth is temporary: the world is entering a new equilibrium and rapid population growth is coming to an end.
March 13
Article
What is the ozone layer, and why is it important?
Over the last 50 years, holes in the ozone layer have opened up. Why does that matter for life on Earth?
February 28
Article
Our World in Data will rely on data from the WHO to track confirmed COVID-19 cases and deaths
Johns Hopkins University will stop publishing data on confirmed COVID-19 cases and deaths. Our team will replace our entire time series with WHO's data on 8 March 2023.
February 27
Article
How we choose which topics to work on, and which metrics to provide
On Our World in Data, we present thousands of metrics on hundreds of topics. How do we choose them?
February 22
Article
Technology over the long run: zoom out to see how dramatically the world can change within a lifetime
It is easy to underestimate the magnitude of this change. Understanding this can help us see how different the world could be in the future.
February 20
Article
What does it mean for a species to be at risk of extinction?
We need to focus on the most threatened species to protect them from extinction. But what does it mean for a species to be at risk, and how is it measured?
February 07
Article
AI timelines: What do experts in artificial intelligence expect for the future?
Many believe there is a real chance that human-level AI will be developed within the next decades, and some believe that it will exist much sooner.
January 19
Article
Engel's Law: Richer people spend more money on food, but it makes up a smaller share of their income
How does spending on food change as incomes rise?
January 05
Article
How many people die and how many are born each year?
Changes in the world population are determined by two metrics: the number of babies born and the number of people dying.
December 15
Article
Wild mammals make up only a few percent of the world’s mammal biomass
Livestock make up 62% of the world’s mammal biomass; humans account for 34%; and wild mammals are just 4%.
December 15
Article
Artificial intelligence is transforming our world — it is on all of us to make sure that it goes well
How AI gets built is currently decided by a small group of technologists. It should be in all of our interest to become informed and engaged.