EU-SILC Tracing Rules Implementation: Pros and Cons Workshop on Best Practices for EU-SILC revision Warsaw, 17-18 October 2018 EU-SILC Tracing Rules Implementation: Pros and Cons Lucia Coppola, Daniela Lo Castro, Mattia Spaziani ISTAT

Tracing Rules Longitudinal component to estimate changes in economic conditions and determinants. Tracing rules (TR) define which units have to be followed up and interviewed, i.e. the units representative of the target population. TR contribute to define the longitudinal population and both cross-sectional and longitudinal sample size and representativeness. Complex TR may contribute to achieve a higher sample dimension and a better representativeness of sub-populations (e.g. new households, households with high mobility etc.). Complex TR may be very demanding for both respondents and NSI, and may not be successfully implemented (e.g. units to be followed are not likely to be interviewed, and sub-populations are not properly represented in the sample) A wide debate on EU-SILC Tracing Rules in the Future (i.e. IESS and implementing regulation). => some empirical evidence to discuss Pros and Cons and keep the debate open

SAMPLE INDIVIDUALS & CORESIDENTS EU-SILC TR are defined at individual level. Sample Individuals have to be traced and followed in the national territory & the family they belong to at the moment of the data collection is defined as Sample Household Any household member aged 14+ at first wave is defined as a SAMPLE INDIVIDUAL (if the panel duration is 4 years…. lower otherwise => 'sample persons' means members of the household in the initial sample aged at least 16 years minus half of duration of a panel (if applicable rounded upwards)). A household member aged less than 14 at first wave and any individual who becomes a household member from the second wave onwards is defined as CORESIDENT. Coresidents are not traced and followed, unless they move with a sample individual.

SAMPLE INDIVIDUALS & CORESIDENTS A SAMPLE individual quits the panel if he/she does not belong any longer to the target population (i.e. he/she dies, moves abroad or to an institution). Otherwise, if a sample individual leaves the original household (i.e. first wave household) to form a new household, the latter is defined as SPLIT-OFF household and belongs to the sample for the whole panel duration. SAMPLE HOUSEHOLDS have to be interviewed during the whole panel duration, unless: - Non-contacted the first year of the panel - Non-enumerated a single year due to the impossibility of locating the address, the address being non-residential or unoccupied, lost (no information on what happened to the household), or the household refusing to co-operate - Non-contacted two consecutive years due to the impossibility of accessing the address, because the whole household is temporarily away or is unable to respond due to incapacity or illness or for other serious reasons

Under DISCUSSION Minimum age to be a Sample Person The role of SPLIT-OFF households When to re-contact a sample household DATA => UDB, longitudinal release 2013-2016 26 countries 4 years panel only

SAMPLE PERSONS & CORESIDENTS First wave sample Second wave sample HH members aged 14+ Sample persons HH members aged 14+ at first wave and still in scope Sample persons HH members aged <14 Coresidents HH members aged <14 at first wave and still living with a SP Coresidents New HH members Coresidents

SAMPLE PERSONS & CORESIDENTS First wave sample Second wave sample HH members aged 14+ Sample persons HH members aged 14+ at first wave and still in scope Sample persons Non-zero longitudinal weight Non-zero longitudinal weight HH members aged <14 Coresidents HH members aged <14 at first wave and still living with a SP Coresidents Zero longitudinal weight New HH members Coresidents

SAMPLE PERSONS & CORESIDENTS First wave sample Second wave sample What if the minimum age is increased to 16 (i.e. age at eligibility for individual interview)? If individuals aged 14-15 at first interview are defined as coresidents and they live with another sample person => they stay in the panel and they do not live with another sample person => they quit the panel HH members aged 14+ Sample persons HH members aged 14+ at first wave and still in scope Sample persons Non-eligible for individual interview SP aged 14-15 HH members aged <14 Coresidents HH members aged <14 at first wave and still living with a SP Coresidents Zero longitudinal weight New HH members Coresidents

HH with SP aged<16 at first wave SAMPLE PERSONS & CORESIDENTS Sample Households where all the sample persons are aged <16 at first wave, by country and year Country Year HH with SP aged<16 at first wave Total HH % BE 2015 1 1528 0.07 2016 1438 BG 3141 0.03 EE 1371 1361 ES 2813 0.04 2621 FR 2013 2 8733 0.02 2014 3 7913 4 7011 0.06 7 6161 0.11 HU 1764 IT 4167 PL 2766 What if the minimum age is increased to 16 (i.e. age at eligibility for individual interview)? In the longitudinal UDB 2013-2016, taking into account the full panel (4 years) only 26 households in 10 countries (out of 25 countries considered in the analyses) would be lost. Similar results in previous UDB

The role of SPLIT-OFF households Sample Persons who leave the family of origin (first wave) to live in another private household in the national territory form a so called SPLIT-OFF Household This is a sample household and belongs to the longitudinal and cross-sectional sample How successful is the follow up of sample individuals who moves? How many SPLIT-OFF households are in longitudinal sample?

The role of SPLIT-OFF households First Wave Second Wave Sample persons Same household Wave 1 Potential Split-off Households, but some are not successfully followed (e.g. no enough information to locate the new household or refuse to cooperate, etc.) Interviewed SPLIT-OFF HH Moved to another private household Non-Interviewed Out of scope Non-interviewed household

The role of SPLIT-OFF households First Wave Second Wave Distribution of sample persons at second wave, by household membership status Sample persons Only 1.6% of sample individuals move to another private household: i.e. a potential SPLIT-OFF household Same household Wave 1 Moved to another private household Out of scope Non-interviewed household UDB 2013-2016 19 selected countries, with split-off households 4 years panel only

The role of SPLIT-OFF households First Wave Second Wave Sample persons Only 1.6% of sample individuals move to another private household: i.e. a potential SPLIT-OFF household Same household Wave 1 Distribution of sample persons who moves, by household membership status Moved to another private household But only 0.6% of sample individuals move to another private household which is actually interviewed: i.e. a SPLIT-OFF household Out of scope Non-interviewed household UDB 2013-2016 19 selected countries, with split-off households 4 years panel only

i.e. a SPLIT-OFF household The role of SPLIT-OFF households First Wave Following Waves During the whole panel (i.e. 2°, 3° and 4° wave), several experiences may occur. We consider (hierarchically) the sample person is : interviewed at least once in a split-off HH no longer interviewed because becomes out of scope no longer interviewed for other reasons interviewed only in the same household as 1° wave Sample persons About 13% of sample individuals are not in interviewed households after 1° wave, although they were supposed to be followed => weights have to compensate for their attrition…. During the next 3 years, only 1.1% of sample individuals move to another private household which is actually interviewed at least once i.e. a SPLIT-OFF household UDB 2013-2016 19 selected countries, with split-off households 4 years panel only

The role of SPLIT-OFF households Distribution of Split-Off Households, Total Households and incidence of Split-Off Households by year, in 18/26 countries with SPLIT Distribution of Split-Off Households, Total Households and incidence of Split-Off Households by country, last year The incidence of Split-Off HH in the last year of the panel is heterogeneous, and higher than 3% in 8 countries. The sample size in one single panel may be low, but since the incidence is quite high, estimates may be achieved by pooling different panels. Split-Off HH may contribute to both longitudinal and cross-sectional estimates. COUNTRY YEAR SPLIT HH TOT HH % AT 2016 49 1203 4.07 BE 71 1438 4.94 BG 26 3141 0.83 CH 68 1533 4.44 CY 33 823 4.01 CZ 20 1765 1.13 EE 59 1361 4.34 EL 30 2131 1.41 ES 98 2621 3.74 HR 8 1018 0.79 HU 4 1593 0.25 IT 70 4167 1.68 LU 715 0.56 LV 31 1282 2.42 MT 56 1035 5.41 PL 29 2766 1.05 PT 58 1697 3.42 SK 10 1384 0.72 YEAR SPLIT HH TOT HH % 2013 5 42911 0.01 2014 290 36519 0.79 2015 523 33627 1.56 2016 724 31673 2.29 Distribution of Split-Off Households, Total Households and incidence of Split-Off Households by year, in FR YEAR SPLIT HH TOT HH % 2013 302 8733 3.46 2014 352 7913 4.45 2015 375 7011 5.35 2016 384 6161 6.23 UDB 2013-2016 19 selected countries, with split-off households

PATTERNS OF PRESENCE IN THE PANEL AND RE-ENTRIES Patterns of Presence (P=Interviewed hh) and Absence ( -- =Non-Interviewed hh) of Households in the panel Re-Entries: from the second wave, households non-interviewed one single year for «temporary» reasons will be recontacted and interviewed next year => intermittent presence in the interviewed sample 12 COUNTRIES WITHOUT RE-ENTRIES 14 COUNTRIES WITH RE-ENTRIES Re-Entries: do not contribute to the 4-years longitudinal estimates (e.g. Persistent at Risk of Poverty Rate, precision requirement in the IESS) scarcely contribute to two-years longitudinal estimates (pooled with the other rotational panels) contribute to the cross-sectional estimates (pooled with the other rotational panels) UDB 2013-2016 26 countries

PATTERNS OF PRESENCE IN THE PANEL AND RE-ENTRIES Patterns of Presence (P=Interviewed hh) and Absence ( -- =Non-Interviewed hh) of Households in the panel Balanced Panel= 63.1% of 1st wave HH Exits=31.1% 14 COUNTRIES WITH RE-ENTRIES Re-Entries=5.8% 12 COUNTRIES WITHOUT RE-ENTRIES Balanced Panel= 74.6% of 1st wave HH Exits=25.4% (=> including potential re-entries) UDB 2013-2016 26 countries 4 years panel only

PATTERNS OF PRESENCE IN THE PANEL AND RE-ENTRIES Incidence of HH in the Balanced panels, by country with Re-Entries Incidence of HH in the Balanced panels, by country without Re-Entries   Balanced panel Exits Re-Entries BE 61.8 34.5 3.7 CH 65.6 26.4 8.0 EE 71.1 24.1 4.8 ES 60.9 33.4 5.7 FR 61.2 33.7 5.1 HR 58.7 37.6 HU 61.6 36.9 1.5 IT 58.8 31.3 9.9 LV 71.5 25.1 3.5 NO 23.7 15.2 PL 73.8 24.4 1.8 PT 84.4 12.7 2.9 SE 57.9 28.4 13.6 SI 51.6 45.5 3.0 Total 63.1 31.1 5.8   Balanced panel Exits AT 62.9 37.1 BG 83.2 16.8 CY 81.4 18.6 CZ 86.9 13.1 DK 85.5 14.6 EL 63.3 36.8 FI 68.5 31.5 LU 56.8 43.2 MT 79.4 20.6 NL 60.2 39.9 RO 95.8 4.2 SK 90.6 9.4 Total 74.6 25.4 High variability in the incidence of HH successfully interviewed during 4 years. Better performance in countries where there are no Re-Entries UDB 2013-2016 26 countries

DISCUSSION Minimum age to be defined as a Sample Person Since household members aged<16 at first wave are not likely to move to another private households without other samples persons (i.e. household members aged 16+ at first wave), there is not a clear advantage in lowering such a threshold. The role of SPLIT-OFF households A low percentage of sample persons who move to another private household are successfully interviewed. The incidence of split-off households is very heterogeneous among countries and increases with time (i.e. wave). These households are worth of interest per sè, because they are representative of longitudinal changes in the target population. Re-contact of non-interviewed households (Re-Entries) About half of countries allow for re-entries in the panel (i.e. a household non-interviewed a single year is re-contacted and possibly re-interviewed next year), but also show lower balance panels incidence. Re-Entries scarcely contribute to longitudinal estimates, and partially to cross-sectional estimates. The potential increase in the sample attrition does not appear problematic.