Demographic Research: Volume 31, Article 44
http://www.demographic-research.org 1321
Figure 1 shows well-known characteristics of the distribution of income by age,
gender and level of education: higher education leads to higher income, men earn more
than women, levels of income flatten (but do not decrease) before retirement. We only
mention these findings, as a detailed discussion would be beyond the scope of this
article. It is important to note that while the income functions are differentiated by
education in Figure 1, they also reflect accumulated human capital, because they
depend on the length of working life. If the latter had not been considered, the curves
would be straight lines running parallel to the horizontal axis and would not reflect real
income by age accurately.
We applied the income functions to construct a human-capital and age-specific
composition of the population aged 20–64. Consider as an example the values of the
income functions at age 50 as outlined above. For men, the ratios are 1:1.42 for middle
education and 1:2.34 for high education, relative to the income of a male with low
education. Hence, if a man aged 50 with low education contributes 1 unit to the human-
capital-specific age composition of the working-age population, a male aged 50 with
middle education contributes 1.42 and a male aged 50 with high education contributes
2.34 units. Similar ratios can be computed for other ages, but they are incomparable
across ages, because the income of a less-educated male differs by age. Similarly, the
income of a female aged 50 is neither comparable to that of a male aged 50 nor to the
income of individuals at other ages. In order to achieve comparability across ages and
sexes, we pivoted all values to the lowest income, which is that of a female aged 20
having an education equal to or lower than junior secondary level. If she contributes 1
unit to the age composition, a man aged 50 contributes 2.2, 2.87 or 4.72 units,
respectively, depending on his level of education.
The human-capital composition of the population aged 65 and above is constructed
differently. We assumed that this population was retired, so we examine its retired
human capital. To this end, we made use of the median of education-specific gross
public pensions over the whole age span 65 and above. The person-units assigned to a
person aged 65 or older with a specific sex and education were once more related to the
income of a female aged 20 having an education equal to or lower than secondary level.
The median gross public pensions for both males and females and by each level of
education were taken from the EU-SILC data (Table 1).
Our method of constructing a human-capital and age-sex composition of the
working-age population combines individual-level estimates of income differentiated
by human capital, age, and sex, with the observed working-age population distributed
by the same three components. One may argue that estimates of the income functions
derived for full-time employment are assigned to persons employed part-time or not
employed at all. Our rationale is that, when assigned to the whole working-age
population, these estimates present the full productive capacity, independent of