CMI Working Paper 205

CMI Working Paper 205 was published in September 2025. The working paper presents the results of an analysis into the efficacy of the “S4” Series socio-economic mortality tables. It is the first analysis of its kind from the SAPS Committee.

This paper analyses the “IMD dataset” as described in Working Paper 195. The IMD dataset is a subset of the total dataset, broadly containing submissions of data with good quality information on IMD decile and region. 

To assess the efficacy of various S4 tables, we calculate the 100 Actual/Expected (100 A/E) results using three different measures for the expected deaths:

1. “All” – Using the all-amounts tables (i.e. S4PMA, S4PFA, or S4DFA) for all members.
2. “Amount banded tables” – Using the appropriate amount band table for a member’s pension amount (e.g. S4PMA_H).
3. “IMD tables” – Using the appropriate IMD table for a member’s pension amount and IMD decile (e.g. S4PMA_G1).

If the amount banded tables and IMD tables are effective, assigning members to the relevant tables would lead to results that are closer to 100 (as the tables would better reflect the mortality of the membership, and the expected deaths would be closer to the actual deaths experienced by the pension scheme). When considering each pensioner type in turn, we observe that:

• For male pensioners, the “Amount banded tables” and “IMD tables” measures are a better predictor of actual mortality than the “All” measure.
• The results are less clear for female pensioners, though there is still some evidence that assigning members to the relevant socio-economic table improves the predictive ability of the tables.  
• For female dependants, there are no “Heavy” or “Middle” amount banded tables, so there are modelling limitations for the “Amount banded tables” measure. The “IMD tables” measure appears to provide a slightly better fit to actual experience than assigning all individuals to S4DFA. 

Summary files of the data

Files used in the analysis are available below. Please note that these files have been made available on the understanding that:

• although the CMI has made reasonable attempts to validate the data, its accuracy cannot be guaranteed and the CMI accepts no liability for its use; and
• any published comment or analysis should acknowledge the CMI as the source of the data.

We have released one output alongside this paper. This is:

• A spreadsheet that includes the data for the charts in the report: “CMI WP205 Chart values v01 2025-09-29.xlsx”. 

Working Paper 205 is available to Authorised Users only.