How accurate are demographic projections used in forecasting pension expenditure?

Anderson, M., Tuljapurkar, S. and Li, N., 2001.  How accurate are demographic projections used in forecasting pension expenditure?  In: Tito Boeri, Axel Borsch-Supan, Agar Brugiavini, Richard Disney, Arie Kapteyn and Franco Peracchi, eds., Pensions:  More Information, Less Ideology.  Kluwer Academic Publishers, pp. 9-27.
Li, N., Feldman, M.W. and Tuljapurkar, S. 2000. Sex ratio at birth and son preference. Mathematical Population Studies 8: 91-107.