The microsimulation model in which medusa is based is
built up with the microdata from the Household Budget Survey (HBS), a
common statistic in all EU countries which is increasingly standardized
and which has relevant potential due the large amount of socioeconomic
information that it collects. The HBS provides information about
household final consumption expenditure on goods and services and
information on some socioeconomic and demographic characteristics of
each household. The HBS provides information at two levels: one for
households and their expenditures and the other for household members.
For more information about the HBS click here.
Specifically, medusa contains the Spanish HBS micro-data
for the time series 2006-2021 (to be updated soon for 2022). However,
the annual databases have been slightly modified to include a larger
number of socioeconomic variables and for a better understanding by the
user. Firstly, some socioeconomic variables have been renamed to make
variable names more intuitive for the user. Secondly, new variables have
been created based on the information collected in the survey. For
example, new income variables are created: quintile (QUINTIL) , decile
(DECIL), ventil (VENTIL) and percentile (PERCENTIL) . Also, and since
medusa aims to facilitate gender-sensitive analyses, the
model includes two variables that allow capturing gender implications:
the gender of the reference person of the household and the degree of
feminization of the household. Although the HBS already includes the
gender of the reference person among its variables, the second variable
is calculated using the information on the gender of the household
members file. Thus, we calculate the percentage of household members who
are women over 14 years (this age is used because it is considered the
age at which individuals begin to have decision-making capacity) and
then we divide the households into 5 groups based on the share of
women:
For more details on the socioeconomic or demographic variables for which the calculation of distributional impacts is available click here.
For expenditure variables, the HBS data are reported using the Classification of Individual Consumption by Purpose (COICOP). The COICOP is the international reference classification of household expenditure developed by the United Nations Statistics Division to provide a framework of homogeneous categories of goods and services according to households purpose. It includes categories such as food, clothing, housing, water, electricity, gas or other fuels. For more information about the COICOP classification click here.
Although the HBS covers a representative sample of the population,
the total population does not coincide with the data collected in the
National Accounts. Therefore, in order to make the HBS data consistent
with the National Accounts data, the population data from the survey
would first have to be adjusted. To do this, medusa takes
the EUROSTAT census data as of 1 January and calculates adjustment
coefficients. The population data is available here.
Despite the fact that the HBS provides a very detailed image of the
annual consumption of households, the aggregate costs of the survey are
not aligned with the principles and data of the National Accounts, which
builds its macroeconomic aggregates based on more complete sources of
information. Therefore, sometimes (e.g. when price shocks come from a
macro model), before the simulation the HBS data should be adjusted to
make them consistent with the macroeconomic dimension. In these cases,
medusa takes the National Accounts consumption data and
calculates an adjustment factor at the highest possible level of
disaggregation. To download the latest data click here.