1. SMALL AREA ESTIMATION FOR CITY STATISTICS
Prepared by Ivana Levacic – Classification, Sampling and
Statistical Methods Department
Presented by Branko Crkvencic – Spatial Statistical Register
Department

2. Sub national statistics grant is not first time that CBS
implemented Small area estimation
Already used for poverty mapping where we have estimated
poverty rates for each municipality in Croatia
Labour Force Survey is designed to provide reliable estimates
of finite population parameters only for large domains (whole
country and eventually NUTS2 region
We need another solution

3. Solution is to apply small area estimation method to estimate labour status for the 556 Croatian cities / municipalities at annual frequency
These estimates are based on 2017 Labour Force Survey data
For improvement of direct survey estimates CBS used a basic
area level Fay-Herriot model
The Fay – Herriot model (Fay and Herriot 1979) has two components: a sampling model for the direct survey estimates and a linking model for the small area parameters of interest

4. Labour Force Survey in Croatia
Basic concepts and definitions
Currently active population or the labour force consists of persons whose activity status in the reference week is either employed or unemployed
Persons in employment are those who were engaged in any work for payment in cash or kind during the reference week. Those are employees, the self-employed, and family members who are helping in some kind of family business or some other kind of gainful activity, as well as persons who worked on contract, for direct payment in cash or kind

5. Labour Force Survey in Croatia
The survey covers all persons who worked for at least one hour
in the reference period, irrespective of their formal status or
means of payment. This means that a retired person, a student
or a housewife can also be classified as employed.
Persons in employment are also those who were absent from
work during the reference week but had a job to return to with
the same employer after the reason for absence no longer
existed.

6. Labour Force Survey in Croatia
Unemployed persons are those who meet the following three criteria:
a) In the reference period did not work for payment in cash
b) Were actively seeking work during four weeks prior to the
Survey
c) Were currently available for work within the next two weeks

7. Labour Force Survey in Croatia
LFS is based on the random sample of private households
Sample consists of four separately selected subsamples,
rotation groups or panels
Sample frame is stratified in four strata at NUTS 2 level and
further separated into urban and rural parts

8. Labour Force Survey in Croatia
Before selecting the sample, the so-called segments are formed
Segments are territorial units formed by grouping of one or
several neighbouring enumeration districts which were
established for the purpose of carrying out the 2011 Population
Census
Weighting procedure is carried out in order to calculate the
estimate for the whole household population and this procedure
provides for the compensation of the design and sample size
impact as well as the impact of the non-response of households
to the Survey

9. Auxiliary Information
Success of increasing the precision of the domain estimates
with the area level model depends on the availability of
correlated auxiliary information
Model base estimates involve known population totals (auxiliary
data) and estimates of the regression between the variable of
interest and the auxiliary data across the small areas; area level
models are based on direct survey estimates aggregated from
the unit level data and related area level auxiliary variables
obtained from surveys and/or administrative records such as
censuses or registers

10. Employment The selected variables for estimated employment are:
Number of working – age population in 2011
Number of persons employed in legal entities in 2016
Number of persons with high education in 2011

11. Labour Force Survey map

12. Employment
This graph shows comparison of estimated absolute number of persons in employment between direct estimate from survey and collected data (in red) and employment totals estimated using small area estimation method (in green). Totals are estimated for all municipalities in Croatia, so in red line there is no estimates for all municipalities – only for municipalities that are in sample.

13. Employment
On this graph we can see comparison of coefficients of variation (CVs – relative sampling errors) for estimated employment totals for direct estimates from survey (collected data) in red and for estimated employment totals using small area estimation method in green. It can be concluded that SAE method decreased sampling errors (CVs) for estimated data for 7 cities. Hence they are more reliable and accurate using SAE methods than direct estimates from survey data.

14. Unemployment The selected variables for estimated unemployment are:
Labour force in 2011
Poverty rate in 2011

15. Unemployment
This graph shows comparison of estimated absolute number of unemployed persons between direct estimates from survey and collected data (in red) and unemployment totals estimated using small area estimation method (in green). Totals are estimated for all municipalities in Croatia using SAE method although there is no direct estimates from survey data as not all municipalities were included in LFS 2017 sample.

16. Unemployment
On this graph we can see comparison of coefficients of variation (CVs – relative sampling errors) for estimated number of unemployed persons between ones for direct estimates from survey (collected data) in red and the ones for estimated unemployment totals using small area estimation method in green. It can be concluded that SAE method decreased sampling errors (CVs) of estimated unemployment totals for 7 cities. Hence they are more reliable and accurate using SAE methods than direct estimates from survey data.

17. Labour force
For the estimated labour force a forward stepwise procedure is carried out to select auxiliary variables.
The selected variables for estimated unemployment are:
Number of employed in 2011
Poverty rate in 2011

18. Labour force
This graph shows comparison of estimated absolute number of labour force between direct estimates from survey and collected data (in red) and labour force totals estimated using small area estimation method (in green). Totals are estimated for all municipalities in Croatia using SAE method although there is no direct estimates from survey data as not all municipalities were included in LFS 2017 sample.

19. Labour force
On this graph we can see comparison of coefficients of variation (CVs – relative sampling errors) for estimated number of labour force totals between ones for direct estimates from survey (collected data) in red and ones for estimated labour force totals using small area estimation method in green. It can be concluded that SAE method decreased sampling errors (CVs) of estimated labour force totals for 7 cities. Hence they are more reliable and accurate using SAE methods than using direct estimates from survey data.