Baseline Case 1 Case 2 Case 3 Case 4 Capital stock 50 - 61.61 - 62.09 Retirement age (actual) 64.2 - - 64.44 66.96 Labor supply 12.17 - 13.53 - 14.12 Rate of return 0.0653 - 0.0563 - 0.0593 Wage rate 1.07 - 1.1 - 1.09
25
the household-level responses and the aggregate factor price adjustments to population aging
are not sensitive to the underlying lW -value used in the simulations. Households respond
to population aging by increasing their private saving (and therefore aggregate capital and
the wage rate) and also by delaying retirement, which leads to an increase in the tax base
of the social security program under both lW = 0.575 and 0.6458. Moreover, similar to
the experiments with different values of capital’s share in total income, the social security
tax rate required to restore projected retirement benefits to their respective baseline levels
under Case 4 is roughly 13.8% for both lW = 0.575 and 0.6458.
The coefficients of the age-dependent household efficiency profile (e(s)) are also treated
as observable in the initial baseline calibration. Given that it is difficult to observe effi-
ciency, the coefficients in (2.28) were estimated from the normalized average cross-sectional
hourly wages data from the 2001 CPS. However, the age-dependent component of household
efficiency used in several other studies on social security and population aging (De Nardi
et al., 1999; Conesa and Garriga, 2008a,b) are estimated from Hansen (1993). Therefore,
the next step is to verify the sensitivity of the simulation results using the age-dependent
household efficiency data from Hansen (1993). The efficiency units in Hansen (1993) are
constructed by taking a weighted sum of the hours worked by each age-sex subgroup using
annual data from 1979 to 1987, where the weights reflect the relative productivity of that
subgroup. To use this data, I first calculate the average of male and female weights for each
age group, and then use piecewise linear interpolation to obtain the weights for all ages
between 25 and 65. To control for the sample selection effects beyond age 65, I assume that
age 65 onwards, efficiency declines at the same rate as it decline before age 65. Finally, I
fit the a quartic polynomial to the interpolated data, which gives
ln e(s) = 0.00271799 + (0.01490187) s −
−
where s is household age. The age-dependent efficiency profiles estimated from the inter-