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- Title: TwinLife - A genetically informative, longitudinal study about the development of social inequality
- Principle Investigators: Prof. Dr. Martin Diewald (<firstname.lastname@example.org>);
Prof. Dr. Christian Kandler (since 07/2021) (<email@example.com>);
Prof. Dr. Rainer Riemann (until 07/2021) (<firstname.lastname@example.org>);
Prof. Dr. Frank M. Spinath (<email@example.com>)
- URL: https://www.twin-life.de/documentation/
Please cite both the dataset (Diewald et al., 2022: TwinLife. GESIS, Cologne. ZA6701 Data file Version 6.0.0, https://doi.org/10.4232/1.13932.) and the reference paper (Hahn et al., 2016: https://doi.org/10.1017/thg.2016.76).
TwinLife is a 12-year representative behavior genetic study investigating the emergence and development of social inequalities over the life course.
The long-term project began in 2014 and surveys more than 4,000 pairs of twins and their families in different stages of life on a yearly basis. All of the subjects reside in Germany. Not only social, but also genetic mechanisms as well as covariations and interactions between these two factors can be examined with the help of identical and fraternal same-sex twins.
In order to document the individual development of different aspects it is important to examine the families extensively over the course of several years. Six important contextual domains are focused on: 1.) Education and academic performance / skill development, 2.) career and labor market attainment, 3.) integration and participation in social, cultural and political life, 4.) quality of life and perceived capabilities, 5.) physical and psychological health and 6.) behavioral problems and deviant behavior.
In order to take a close look at the development of social inequalities, TwinLife does not only examine different etiological factors, but also different indicators of personal and social success and failure respectively. On part of the conditional factors genetic disposition as well as aspects of the environment that the children and adolescents are living in are considered. On part of the consequences not only objective but also subjective information is observed. Children are born into an environment which influences them, but on the other hand they react and interact differently depending on their individual characteristics and thereby shape their environment. To allow for an accurate examination of the reciprocal processes by which individual dispositions and environmental conditions influence each other, data on the illustrated characteristics will be collected over a period of twelve years.
In the following, the contents of the TwinLife Data are described in more detail by the life domains outlined above:
1. Skill formation and education
1.1 Educational success
- School report; if not available: supplementary questions
- Current school marks or rather marks of highest graduation
- School climate/student-teacher-interaction
- Pressure and stress at school
- Subtests Matrices, Series, and Classification
- Subtests Matrices, Series, Reasoning, Classification
1.3 Cognitive development
- General information derived from "U-Heft"; if not available: supplementary questions
- Interviewer rating on task orientation and oral skills following intelligence test
- Tutoring and homework help/special educational treatment/attendance of special school
- Competence rating of social skills, oral skills, concentration ability, communications skills, mathematic ability, general knowledge
1.4 Media use
- Frequency and duration of media use (e.g., Internet, Laptop, TV, games console etc.)
1.5 Academic self-concept
- Verbal and spatial skills, spatial and general
- Verbal, mathematic, and general academic ability
- Perceived competence
1.6 Intrinsic motivation, learning motivation, achievement motivation
- Educational values of German, maths, and school in general
- Learning and achievement motivation in German, maths, and school in general
- Learning goals
- General self-efficacy
- General self-esteem
- Consistency of interest, self-control
- Gummy bear test
- Neuroticism, extraversion, openness, agreeableness, conscientiousness
2. Career and labor market attainment
2.1 Employment status
- Current employment status/changes regarding employment
- History of education
- Education and qualification
- Educational and career aspirations
2.3 Information on current job
- Perceived job security and satisfaction
- Wages/income/welfare dependency
- Job-related burden (i.e. shiftwork)
2.4 Economic preferences
- Risk aversion
2.5 Job autonomy
3. Integration and participation in social, cultural, and political life
3.1 Migration background and citizenship
- Current status of citizenship and changes of citizenship
- Experiences with discrimination
3.3 Social participation
- Frequency of attendance in sports clubs, theatre, music groups or volunteer organizations
3.4 Social networks
- Social capital of individuals, e.g., close friends, frequency of social contacts
3.5 Political participation
- Interest in politics, political preferences, voting behavior
- Religious affiliation, church attendance, religiosity/spirituality
3.7 Cultural capital
- Cultural participation, reading, classical music
- Availability of cultural property
- Music lessons
4. Subjective perceptions of quality of life
4.1 Life satisfaction
- Global life satisfaction
- Domain satisfaction (health, work life, family life, leisure time, school, romantic relationship, friendships, income)
- Satisfaction with sibling relationship
4.2 Burden and stress
- frequency of arguments with partner or parents
- Stress regulation and coping
- interfamiliar and extrafamiliar: subjective evaluation
4.3 Life Goals: importance and progress
4.4 Sensory-processing sensitivity
- in the childhood and adolescence
5. Physical and psychological health
5.1 Subjective health
5.2 Objective health and diagnosis
- Measures of height and weight child´s medical records
5.3 Health-related behavior
- alcohol consumption, smoking, medication, medical checkups
- sexual behavior
6. Deviant behavior and behavioral problems
- Emotional symptoms, problems with peers, social difficulties
- Hyperactivity, attention problems, behavioral difficulties
6.3 Deviant and delinquent behavior
- Occurrence and frequency of problematic behavior (e.g., fare evasion, skip school, drug use, thieving, property damage, physical assault)
- Supplementary questions on e.g., impulse control and rebellious behavior
- Short version of deviant/delinquent behavior measure
7.1 Information on household
- Household questionnaire (persons in the household, household grid, type of dwelling, income), information on assets
8.1 Activities with children
- Occurrence and frequency of e.g., singing and making music together; story time; doing sports; cultural activities
- Detailed information on nursery and daycare institutions
- Relationship: contact frequency, quality of relationship
8.4 Parenting style
- Monitoring, warmth, rules, negative communication, control (child and parent report on parental behavior)
8.5 Quality of home environment
- Characteristics of a chaotic, disorganized, and hurried home
- Interviewer ratings on the home environment (household)
- Autonomy, structure, control, emotional support
8.7 Sibling relationship
- Warmth, conflict, rivalry of sibling relationship
- Affection, hostility, rivalry of sibling relationship
8.8 Family stresses
- Care burden on household level
8.9 Intentional level to achieve certain life events
8.10 Stays abroad
8.11 Information on twins' children
9. Zygosity and twin specific items
- Ratings of physical twin similarity in childhood (e.g., eye color, hair structure, time of getting first teeth)
9.2 Twin specific questions
- E.g., same or different clothing, confusion of the twins, undertakings with twins
10. Covid-19 supplementary surveys
10.1 Health during the COVID-19 pandemic
10.2 Socioeconomic changes
10.3 Covid-19-related behavior change
10.4 Resilience, coping
10.5 Perceived threat, stress and strain, psychological impairment
10.6 Assessment of government restrictions
The TwinLife panel combines a sequential cohort-design with an extended twin family-design (ETFD). The related surveys are conducted yearly, whereat the mode alternates between face-to-face at home, including some tests, and telephone interviews. Parts of the face-to-face surveys are conducted in parallel modes, i.e., as computer assisted or paper-and-pencil self-interviews.
The sequential cohort-design comprises four cohorts: The youngest twins in cohort 1 (birth years 2009 and 2010) are about 5 years of age at the time of the first survey in 2014 and 2015. The oldest twins in cohort 4 (birth years 1990 to 1993) are about 31 to 32 years of age at the time of the last survey in 2022 and 2023. The twins in cohorts 2 and 3 are born in the years 2003 to 2004 and 1997 to 1998, respectively. This design enables the TwinLife panel to cover an age range between 5 and 32 years with a data collection phase of 10 years. This age range covers important life-course transitions from school entry to the labor market entry phase as well as critical life stages for mating and family formation.
As part of the ETFD, in addition to the twins themselves the biological and if applicable social parents as well as the sibling that is closest in age to the twins are surveyed. Moreover, the partners of adult twins are included as well. This family perspective enables comparisons regarding different degrees of genetic similarity, and it is important to analyze the manifold influences of the family environment on the development of the twins in greater detail.
Geographic Coverage: Germany
Universe: Twins and their families (Extended Twin Family Design, ETFD): Monozygotic and dizygotic same-sex twin pairs born in the following years: 1.) 1990 and 1991, 2.) 1997, 3.) 2003 and 4.) 2009 (4 birth cohorts)
plus at least one biological parent
(+ if possible the other biological parent, step-parent(-s), one sibling and the twins' partners)
Selection Method: Twin families are drawn from local resident registers in communities with at least 5,000 inhabitants in Germany. The twin families are recognized as such if two same-sex people with the same date of birth lived in the same household. Then, it was checked whether the selected persons were twins indeed.
Mode of Data Collection: Face-to-Face data collection: Household interviews with the family via three different interview modes (CAPI, CASI, Paper-and-Pencil) plus cognitive tests, scans/photos of certificates and children's health record books. CATI data collection: Telephone interview with one family member (from second CATI wave onwards; before: telephone interview with each family member above the age of 10 that participated in the preceding Face-to-Face wave)
Survey institute: TNS Infratest / Kantar TNS (first Face-to-Face household survey, parts of the first telephone survey); infas Institut für angewandte Sozialwissenschaft (parts of the first telephone survey, second Face-to-Face household survey)
Dates of Data Collections:
data collection 1 (F2F 1a) Sep 28, 2014 to May 28, 2015
data collection 1 (F2F 1b) Sep 16, 2015 to Apr 18, 2016
data collection 2 (CATI 1a) Nov 23, 2015 to Apr 18, 2016
data collection 2 (CATI 1b) Dec 05, 2016 to Apr 30, 2017
data collection 3 (F2F 2a) Nov 07, 2016 to Sep 29, 2017
data collection 3 (F2F 2b) Sep 04, 2017 to May 27, 2018
data collection 4 (CATI 2a) Oct 11, 2017 to May 12, 2018
data collection 4 (CATI 2b) Nov 06, 2018 to Apr 16, 2019
data collection 5 (F2F 3a) Nov 26, 2018 to July 06, 2019
data collection 5 (F2F 3b) Sep 16, 2019 to June 06, 2020
COVID-19 Supplementary Survey (CoV 1) Jul 24, 2020 to Nov 15, 2020
COVID-19 Supplementary Survey (CoV 2a) Nov 30, 2020 to Apr 20, 2021
COVID-19 Supplementary Survey (CoV 2b) Feb 18, 2021 to Aug 01, 2021
Scientific use files (current version: v6-0-0)
For a description of the structure of the TwinLife sample see the TwinLife Technical Report 03, for the method reports of the first four data collections see the TwinLife Technical Reports 05, 09, 10, and 12 at https://www.twin-life.de/twinlife-series.
Master data (ZA6701_master_v$): Includes information on the gross sample, such as consistency checked variables that are stable over time (sex, year of birth, relation to the twins, zygosity, migration background) and wave-specific variables (person type, response status) about all individuals included in TwinLife in each wave.
Survey data in person format with filter error adjustment (ZA6701_person_wid$_v$): There is one data set for each data collection. Each surveyed person has one data row (pid). The data collection identifier is the variable wid. The data were filter-cleaned, i.e. data were deleted if the question was not intended for a person according to the filter instructions. These datasets are documented on paneldata.org.
Data of covid supplementary surveys (ZA6701_person_cov$_v$): There is one data set for each covid supplementary survey. Each surveyed person has one data row (pid). The data collection identifier is the variable cov.
Survey data in person format without filter error adjustment (ZA6701_person_unadj_wid$_v$): There is one data file for each F2F data collection including all variables that were at least partially collected in PAPI mode (self-administered) without filter error adjustment. It is up to the users to decide how to handle the information provided by the respondents.
Survey data in family format (ZA6701_family_wide_wid$_v$): There is one data set for each data collection. Each family has one data row with information of each participating person in the family being stored in separate variables/columns. Person format and family format data sets contain the same data using different structures.
Twin zygosity assessment (ZA6701_zygosity_v$): A data file with the information of the twin zygosity assessment in F2F 1.
Survey mode (ZA6701_mode_wid1_v$): A data file with information on the survey mode for each variable in F2F 1.
Survey weights (ZA6701_weights_v$): A data file containing the survey weights (design, non-response, and panel weights).
All data is provided with English and German variable descriptions. In Stata, these languages are included in one data set while in SPSS, these are separate data files. Variables and instruments are documented at http://www.paneldata.org. Detailed information on the study and special features can be found at https://www.twin-life.de/documentation/. For questions regarding the content of the data, please contact <firstname.lastname@example.org>.
Number of Units:
- 21,262 individuals
- 4096 families
Number of Variables:
- 2,515 (F2F 1 [wid1] person-format)
- 611 (CATI 1 [wid2] person-format)
- 2,347 (F2F 2 [wid3] person-format)
- 123 (CATI 2 [wid4] person-format)
- 1,341 (F2F 3 [wid5] person-format)
- 121 (CoV 1 [cov1/wid10] person-format)
- 131 (CoV 2 [cov2/wid11] person-format)
Data can be accessed via the GESIS Data Catalogue: https://search.gesis.org/research_data/ZA6701
Charges for downloading this data will be paid by the TwinLife project, so the use of the data is free of charge!
Note on availability: Data and documents are only released for academic research and teaching after the data depositor's written authorization. For this purpose the Gesis Data Archive obtains a written permission with specification of the user and the analysis intention. To get access to the TwinLife data, please fill in the Data Use Agreement.