To ask the Secretary of State for Work and Pensions how many individuals in each birth cohort, as shown in Figure 4.3 on page 55 of DWP Research Report number 558, would be modelled as having payback equivalent to having received at least the full value of the assumed rate of return used in the modelling; and what the equivalent figures are under alternative scenarios (a) 1 and (b) 2 as referred to on page 57 of DWP Research Report number 558. (287114)

The Department's population-level modelling calculates payback rather than internal rate of return, and there is no simple correspondence between the two measures—for each individual it depends on their patterns of saving and decumulation through time. As a result it would be a major exercise to calculate the distribution of internal rates of return for birth cohorts, and the cost of producing this analysis would be disproportionate.