MP improvement scale
\ɛm-pi\ \ɪmˈpruvmənt\ \skeɪl\
The MP improvement scale is a projection model widely used by pension plans in the US.
It is produced by the Society of Actuaries’ Retirement Plans Experience Committee (RPEC) in the US, with the first iteration, MP14, being released in 2014, with subsequent annual updates. The MP improvement scale is based on a simplified version (aimed at being more accessible and transparent) of the original (pre-2016) CMI mortality projection model.
The core model is calibrated in the short term to recent experience observed in the US Social Security mortality set (using Whittaker-Henderson techniques). These short term rates are then blended to a long-term rate specified in the model of 1.0% up to age 85, a linear reduction to 0.85% at age 95 and a further linear reduction to 0% at age 115.
It is possible to use the MP improvement scale with alternative assumption sets to the ones selected by RPEC for the core model (with RPEC noting that the resulting mortality improvement rates must be justified as reasonable and appropriate for the particular application).