1. Czech Experience with the Tracing in EU-SILC
Simona Měřinská
Household Surveys Department
Workshop on best practices for EU-SILC Warsaw, Poland, October 2018

2. TRACING in EU-SILC
The specificity of EU-SILC survey is to trace respondents while they move.
The tracing of respondents is a challenging task.
If a respondent (or the entire household) from the original selected dwelling moves to another dwelling, municipality or even another region within the Czech Republic, the tracing process is initiated and the „investigation“ of the person is carried out.
It requires:
pretty tough logistics
prompt reactions in the fieldwork
good management of the whole process
(interviewers have to cooperate with their regional coordinators and those have to cooperate between themselves among other regions)

3. It involves:
moves between regions across the whole country
splits off into more different addresses
It is necessary:
to find out appropriate information
to trace panel persons from the selected household
to interview them at their new address (before the end of the fieldwork period)
Out of scope:
persons moving abroad or to a collective household or institution (eg. prisons, hospices, retirement homes) are not considered to be traced.

4. Tracing Application for CZ-SILC
at CZSO we created a dedicated logistics application for tracing of respondents
it enables standard CAPI interviews also for movers, including across-regions mobility
it allows to transfer all the data (information obtained from previous waves so far) with the moved people easily to a new address, then create a new identification for them and to survey them at the new address where they currently live.
 Monitoring of the tracing process

5. SILC tracing data flows
Central data repository
The concerned new region coordinator receives notification and data move information file, processes it and assigns the new address to one of their interviewers
Interviewer records the data about the move, and data move information file is sent to central repository by eDomSet module
Regional coordinator receives notification about the move and handles the case
If the new known address is in a different region, coordinator assigns new region
New region into which
the respondent moves
Import file with new case data about moved respondents
Region from where the move is taking place

6. Czech tracing APPLICATION
List of all cases in given region – overview of all moved panel persons
A simple form to be filled in about the moved household or each person individually,
when the new address is known or even unknown

7. TIME SERIES
Number of cases of moved households within Czech SILC survey during past 10 years varies around 160 and is rather low
(only about 2 – 3 % of the sample), which means that moving is relatively rare in the country.

8. Number of moved persons in SILC 2017:
somewhere within the country
abroad
to an institution or collective household
no information
Number of moved persons in SILC 2017:
Panel person has moved
another private HH within CR – 404
abroad – 42
institution – 31
not identified – 203

9. TRACING PROCESS successfully interviewed 266 address found out 294
not interviewed at new address 28
address found out
294
address not found out
110
to be traced
404

10. ANALYSIS OF DATA Who are the people who slip through our fingers?
Those we can not find and interview again were already our respondents in the previous wave and unlike non-respondents we have a lot of information about them from last year.
What is the impact of tracing process on our final SILC indicators?
We have calculated the impact on the key published indicators removing all the moved people from the file, re-weighted it and tried to find out what is the effect.
How about the comparison between traced respondents and not traced people?
We have examined the characteristics of those who moved, which of them we can successfully trace and how many people are willing to further cooperate and how many people refuse on the new address.

11. NEW ADDRESS NOT KNOWN (NON-TRACED)
Age
80 % of non-traced people is at age 0-34 years (i.e. families with little children and also young individuals)
Education
60 % of them have secondary education with or without „leaving exam“
Economic activity
They are most often full-time employees (43.6%) and students (12.7%)
characteristics of panel persons we were not able to trace
Housing
They live mostly in their own homes or privately owned apartments
Size of flat
60% of them live in larger flats with an area of m2
Net income of the person They are mostly middle-income people but also those without any income

12. NEW ADDRESS KNOWN (TRACING SUCCEEDED)
Age
Half of the successfully traced people is at age years plus 28.2% are pre-school children (i.e. young families)
Education
44.4 % of them have secondary education, but also 15.1 % have tertiary education
Economic activity
Half of them are full-time employees
characteristics of panel persons who were visited on their new address & interviewed again
Housing
They often live in rented flats (47.4 %)
Size of flat
60 % of them live in medium-sized flats with area of m2
Net income of the person Their income is only slightly higher than income of non-traced

13. TRACING INVOLVES PROBLEMS
Tady ještě něco vymyslím k tomu srovnání nedohledaní, úspěšně došetření a odmítači na nové adrese
TRACING INVOLVES
PROBLEMS
When one selected household is split into 2 households, each person moves to a different address elsewhere (eg. divorced couples, adult children become independent and move from their parents etc.) and when one of the panel persons even refuses to participate in the survey.
successfully interviewed
new address known
not interviewed (refusals, non-contacts,
ill)

14. KEY PUBLISHED INDICATORS FROM CZ-SILC
CZK
Average yearly income per person in CR
CZK
Poverty threshold
9.1 %
At-risk-of-poverty rate (AROP)

15. Průměrný roční příjem na osobu v ČR
Průměr hodnoty ukazatele
Medián ukazatele
Variační koeficient ukazatele
1. decil ukazatele
2. decil ukazatele
3. decil ukazatele
4. decil ukazatele
5. decil ukazatele
6. decil ukazatele
7. decil ukazatele
8. decil ukazatele
9. decil ukazatele
Official
58,9
99 786
Without moved
57,8
99 158
ratio
99,8
99,9
98,1
99,4
99,6
Comparison of key indicators without moved panel persons prepare better tables!
Poverty rate 60%
official
Without moved
ratio
Men
7,6
7,4
97,4
Women
10,7
10,8
100,9
Under 18 years
11,6
11,7
65+
10,9
101,9
Working
3,5
3,6
102,9
Unemployed
48,6 47
96,7
Retired 11
without children
8,7
8,8
101,1
With children
9,6
9,5
99,0
1 adult with 1+ children
31,4
32,2
102,5
EU EQPRIJ =EU_PRIJ/EJ
Poverty60
Povert rate
Official
9,1
without moved
ratio
99,9
100,0
The results are statistically identical. Everything is within the confidence interval. Even if we choose a more detailed sorting of people (eg. unemployed or single-parent with children), we still come within the sample error because these specific groups have a wider confidence interval.

16. CONCLUSIONS

17. In Czech conditions on relatively small sample I may say…
Respondents who have moved from the original selected household to a new address have no such characteristics to change the results, so they do not have any effect on our outputs and key indicators.
Excluding these people has no impact on published results. Obviously, it can not be taken in absolute terms, but in the context that all statistical results are estimates within a certain confidence interval.
All the effort that our national Statistical Office devotes to the methodology of tracing and processing of longitudinal data and all the vigorous effort that our field workers spend on managing the required processes every year is essentially an inefficient capacity burden –”unnecessary luxury”.
It is a challenge to do something about it, but under Regulation the tracing of panel persons within EU-SILC survey is still obligatory.

18. Ready for discussion! Contact us at: www.czso.cz