Investment Appraisal/Discounting

Question

I would appreciate any consideration given to the question I have with respect to a document published by the UK Dept. of Transport.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/639211/research-into-valuing-health-impacts-in-transport-appraisal.pdf

Here, on page 20 (Table 11) of this report, the authors use standard discounted cash flow methods for discounting future costs/future monetisable benefits.

In particular, with an actuarial year of life lived (YLL) set equal to £60,000, they estimate that in 3.92 YLLs in 2012 should be worth £228,476.34.

However, when I use standard discounting formulas in which £60,000 is discounted by 0.015; or discount YLLs by 0.015, I can only seem to get approximately £228,114.

If someone with expertise had 10 mins to sink their teeth into this, would it possible to show how £228,476.34 on Table 11 was obtained please?

Answer 1

I see that the subsequent years are discounted using 1.5%: \begin{eqnarray} 228,476.34\, /\, 225,099.84 - 1 = 1.5\% \\ 225,099.84\, /\, 221,773.25 - 1 = 1.5\% \end{eqnarray} If you allow that the YLL displayed as 3.92 is actually 3.9230339 but rounded then $$1.015^{-2} \times 60.000 \times YLL = 228,476.34$$