The computation of mortality rates has traditionally been the bread and butter of actuaries. The first mathematicians to venture into the actuarial field most likely spent their days analysing mortality rates and conducting life valuations. Nowadays, the work of actuaries is much more varied—which is a welcome development for most—but are we sometimes neglecting this core skill?
Milliman researchers in Paris certainly aren’t and their new research, hot off the press, published on 22 February 2017, represents a significant development in mortality and longevity risk modelling. It is vital reading for anyone working in this sphere.
My colleagues have developed a robust statistical methodology to correct the implicit inaccuracies of national mortality tables which are used widely in sophisticated mortality and longevity risk modelling. The results are striking.
Here I take a closer look at the relevance of these national mortality tables, the problems with them, and the corrections available in order to enhance mortality and longevity risk models. I will touch on the key technical points behind these developments from an Irish/UK perspective, leaving the rigorous mathematical explanations to the underlying research publications—the 2017 publication can be found here and the 2016 publication can be found here.
The use of national mortality tables
In Ireland and the UK, to set basic mortality assumptions in our pricing and reserving work, we tend to use insured lives mortality tables, such as the Continuous Mortality Investigation (CMI) tables. However, national mortality tables based on the population as a whole are also used extensively in mortality and longevity risk modelling, where a greater quantity of data is required.
National mortality tables are used to calibrate stochastic mortality models, to derive mortality improvement assumptions, in sophisticated mortality risk management models, in Solvency II internal models, in pricing mortality/longevity securitisations, and in bulk annuity transactions.
Bulk annuity transactions are popular in the UK market, with a number of large deals executed during 2016, including the ICI Pension Fund’s two buy-in deals completed in the wake of Brexit, totalling £1.7 billion. Legal & General completed a £2.5 billion buyout agreement with the TRW Pension Scheme in 2014.
Longevity hedging (in particular, use of longevity swaps) is also an attractive approach to the de-risking of pension schemes, and would equally require the use of national mortality tables. Transactions range from the large-scale £5 billion Aviva longevity swap in 2014 to the recent, more modest, £300 million longevity swap completed between Zurich and SCOR in January 2017.
While the use of internal models to calculate mortality and longevity risk capital requirements under Solvency II is not prevalent in the Irish market, which is due to the size of companies and the amount of risk retained, it is likely that reinsurers are looking at such models. In the UK, larger companies may opt to use internal models if they are retaining large exposures.
Indeed, national mortality tables also typically inform mortality improvement assumptions for all companies, as the analysis of improvements requires large volumes of data. Therefore, even companies that do not use sophisticated mortality and longevity risk modelling techniques are implicitly impacted by the new developments in relation to the construction of national mortality tables.