Disposable income: this is calculated by subtracting the compulsory transfer expenditure, e.g. social insurance contributions (OASI/DI contributions, occupational pensions, etc.), taxes, premiums for compulsory health insurance and regular transfers to other households (e.g. child maintenance) from the gross income.
Equivalised disposable income: this is calculated on the basis of the household disposable income, taking account of the household size and composition by means of an equivalence scale, where the oldest person is attributed a coefficient of 1.0, each person aged 14 or over is attributed a coefficient of 0.5, and each child aged under 14 is attributed a coefficient of 0.3. This takes account of the savings made by multi-person households.
Median: the median (middle value) divides the total values observed (and ranked according to size) into two equal halves: one half represents the 50% above the median, the other the 50% below it.