Today, we are living increasingly longer lives compared to 150 years ago. However, the question is, can that trend go on?
The Human Mortality Database (HMD), operated jointly by Berkeley Demography researchers, processes data that can help answer that question.
Co-led by Demography researcher Magali Barbieri, HMD is a collaboration between Berkeley and two other organizations, the Max Planck Institute for Demographic Research in Germany and the French Institute for Demographic Studies in Paris.
“Now that we're living longer and longer lives, the age at which most people pass away increases with time. It's becoming more and more important to have accurate estimates of mortality at these very high ages,” Barbieri said. “So right now, we're working with a network of experts to review the methods we are using and to investigate additional methods.”
The core database, which is over 20 years old, includes historical series of mortality indicators, such as rates and probabilities of dying at each age for each sex, life expectancies at various ages and other indicators of survival.
Life expectancy at birth in the United States in the early 1930s was only about 63 years old for a woman and about 59 years old for a man, according to the HMD. But it increased to around 80 years for a woman and approximately 75 years for a man during the 20th century – representing an increase of more than 25%.
But the U.S. has suffered a reversal in life expectancy trends, even before the Covid-19 pandemic, with a decline in the length of life between 2014 and 2017, according to HMD’s data. In 2023, life expectancy at birth in the U.S. remained lower than in 2019, though it regained 1.5 years compared to 2020.
Life expectancy is calculated based on how many people die at each age along with how many people are alive at that age, which are converted to probabilities of death. The database collects data for number of deaths, number of people at risk of dying and population count.
The project has created data series for over 40 countries, mostly in Europe and North America, which have long established vital statistics systems and high quality data. Collaborations with statisticians in national statistics offices in these countries have ensured access to the necessary information.
HMD’s data is crucial in understanding the longevity revolution of the 20th and 21st centuries. About 7,000 publications, including 5,500 peer-reviewed scientific journals, have cited the HMD as their source of information. The data is useful for a wide range of topics, such as public health, policy making and economic research for life insurance.
During the COVID pandemic, HMD created another database, called the short term mortality fluctuation series. This component of the HMD provides statistical information on the fluctuations of deaths from week to week, helping people follow COVID counts in different countries.
The data is also relevant in understanding other epidemics, like a flu epidemic and other health problems. According to the database, epidemic waves varied in timing and intensity. This research was based on countries that have reliable data, which are typically high-income countries. In many countries, the level of mortality is only now slowly returning to its pre-pandemic levels.
HMD recently added a cause-of-death component for about half of the countries in the database. This data is aimed to identify the driving reason behind the extraordinary progress in life expectancy and mortality.
“All of these databases are freely accessible. We have now more than 75,000 people who sign up to download the data,” Barbieri said.
