In September 2012, the Society of Actuaries (SOA) released the results of research indicating that recent U.S. mortality improvements have outpaced expectations. The Mortality Improvement Scale BB report was authored by the Retirement Plans Experience Committee (RPEC), a subcommittee of the SOA whose primary directive is to research mortality experience among U.S. retirement plans. The RPEC also publishes the mortality tables and mortality improvement scales that are in frequent use for actuarial valuations of pension plans in both the public and private sectors.

Currently, the RPEC's most recently published mortality tables in the United States are the RP-2000 tables. These tables contain expected rates of mortality by age, and are mandated by the IRS for use in U.S. corporate pension valuations. The RPEC had also previously published Scale AA, a scale of mortality improvements intended for use with base mortality tables to reflect the expectation that mortality is improving over time. However, the most recent research shows that even greater actual mortality improvement has been occurring than was predicted by Scale AA.

Additionally, the RPEC research has revealed that age alone may not be the best predictor of mortality improvement; some birth groups may experience rates of improvement that differ from other birth groups, or entire populations may experience a boost in longevity that is due to medical achievements such as antibiotics, regardless of age. For reasons such as these, the RPEC believes the best predictors of mortality improvement may be tied to both age and calendar year. This would create the need for a two-dimensional table of mortality improvement rates, which some current actuarial software may not be able to utilize without modification.

To that end, the RPEC has released an interim improvement scale, known as Scale BB. Scale BB, although not itself two-dimensional, incorporates information from the fully two-dimensional rates developed by the RPEC. It also reflects the stronger improvement patterns seen in recent years. Although the impact of using Scale BB in actuarial valuations will vary by pension plan based on plan provisions, maturity, and other factors, Scale BB is expected to result in higher liabilities as it reflects increasingly lengthy lifetimes for benefit recipients. The RPEC study estimates that switching from Scale AA to Scale BB might increase liabilities between 2% and 4%, based on some sample plan analysis.

There is ongoing debate in the actuarial community as to the use of Scale BB, particularly centering around some assumptions used in the creation of that scale. The RPEC anticipates the release of final mortality tables and a final improvement scale by the end of 2013 or early 2014. Therefore, whether or not the use of Scale BB becomes widespread, increases in mortality improvement will likely be reflected within the next several years for many pension plans.

To read the entire SOA report, click here.