MP improvement scale
\ɛm-pi\ \ɪmˈpruvmənt\ \skeɪl\
The MP improvement scale is a projection model widely used by pension plans in the United States to estimate future mortality improvements.
It is developed by the Society of Actuaries’ Retirement Plans Experience Committee (RPEC), with the first version, MP-2014, released in 2014 and followed by annual updates until 2021 (when updates were paused due to the impact of the COVID-19 pandemic on the population mortality data). The scale is based on a simplified version of the original (pre-2016) CMI mortality projection model, designed to be more accessible and transparent.
The core model is calibrated in the short term using recent mortality experience from the U.S. Social Security dataset, applying Whittaker-Henderson smoothing techniques. These short-term improvement rates are then blended into a long-term improvement rate structure:
- 1.0% per year up to age 85
- Linearly reduced to 0.85% at age 95
- Further reduced to 0% at age 115
Since 2021, the MP improvement scale has been accessible via a pre-selected set of calibration assumptions in the Society of Actuaries' Mortality Improvement Model (MIM).
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