|Units: Income inequality among the highest and lowest quintiles.|
|Source Catalonia: Idescat. Source Spain, eurozone and European Union: Eurostat.|
|(b) Break in time series.|
|(..) Confidential data, low reliability or not available.|
Date published: June 21, 2018. Revised series on December 5, 2018.
The S80/20 ratio measures the inequality in income distribution via ratios between percentiles. This indicator is interpreted as the income earned by the top quintile, that is, by the 20% of the population with the highest income, in relation to that received by the lowest quintile, that is, by the 20% of the population with the lowest income.
This indicator exhaustively compiles the current income (both monetary and non-monetary) by households in a calendar year. Household's annual net income corresponds to the calendar year before that of the survey.
In order to compare the incomes of households, what are called 'equivalised scales' are used, which turn total household income into equivalised income. These equivalised scales are an adjusted measurement that turns the number of members living in the household into a number of units of consumption. Even though there are many different ways to make this adjustment, the equivalised scale used is the modified OECD scale. This scale gives a weight of 1.0 to the first adult, 0.5 to the other adults and 0.3 to children under the age of 14. The total income of a household is divided by the number of units of consumption in the household, thus obtaining the equivalised income or income per consumption unit. For purposes of analysing the personal distribution of the income and the risk of poverty, each household member is assigned the equivalised income of their household.
The data of Catalonia comes from the Survey on Living Conditions. This is a statistical operation carried out annually by the INE, whereupon Idescat performs a specific analysis of the results for Catalonia.
From 2016, as the result of an agreement signed with the INE to improve this statistic, Idescat carries out its own field work to extend the Survey with information from ore than 1,700 households; this means that the sample now includes more than 3,000 households and 7,300 individuals. The main objective of this extension is to improve the statistical validity of the results.
After 2013, the data related to the household income from the Survey on Living Conditions has been assembled using a mixed methodology that combines the information provided by the interviewee and the administrative records of the Tax Agency and Social Security.