Slowdown in mortality improvement rates - a multi-country analysis

A detailed analysis and modelling of historic mortality data to aid understanding of the slowdown in mortality improvement rates, and to quantify the extent to which current mortality patterns have deviated from expectations.

Mortality rates have been falling or ‘improving’ in many demographically developed countries since the 1950s. However, since 2010 there has been a slowdown in the speed of improvement, with the phenomenon being particularly marked at ages of 50 and over.

Even before the significant global mortality shock caused by the emergence of COVID-19, the rate of mortality improvement had been seen to slow in several developed countries. Life expectancy had grown for both men and women during the period between 1991 and 2011 but then, in 2015, a sharp spike in the numbers of deaths, particularly among older people, resulted in a significant fall in life expectancy. This was seen in the US and several European countries.

While policy makers are aware of the need to reverse adverse trends in mortality, the means of achieving it remain unclear. A better understanding of what has driven recent changes in rates of mortality improvement is required.

To facilitate this understanding, researchers have analysed long-run mortality trends of a group of developed countries using data up to 2017 from the Human Mortality Database.

The study The slowdown in mortality improvement rates 2011–2017: a multi-country analysis analyses population mortality trends at ages over 50 across a group of 21 developed countries since 1965, at the level of age specific mortality rates and mortality improvement rates.

It finds that many countries have experienced lower mortality improvement rates in 2011-2017 than in the previous decade, and also experienced lower improvement rates in that period than would have been forecast based on models fitted to data prior to 2011.

In conclusion, it finds that part of the slowdown in mortality improvement rates of the over 50s since 2011 would have been expected from historical trends in many countries, especially among men. There has been a notable slowdown, compared with the model forecasts, in many countries since 2011, especially among women. There are, however, some countries with higher mortality improvement rates than projected. 

A deeper understanding of stagnating mortality patterns is important for several reasons. From a policy viewpoint, an understanding can inform decisions to reverse these trends in order to better target and implement health and social policies. A better understanding of stagnating patterns could also potentially improve forecasting methodologies employed by the insurance industry.

To the best of the authors' knowledge, this is the first comparative cross-country study of mortality trends using stochastic models to identify historical trends and forecast future trends to examine to what extent the post-2011 experience deviates from the long
run trend.

The research paper The slowdown in mortality improvement rates 2011–2017: a multi-country analysis is available for download at City Research Online.

It has been published in European Actuarial Journal.