TwinLife

TwinLife is a 12-year representative behavior genetic study investigating the emergence and development of social inequalities over the life course. For a detailed documentation of the study please visit <a href=https://www.twin-life.de/documentation/ target=_blank>https://www.twin-life.de/documentation/ </a>.

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 2020 and 2021, three supplementary surveys on the influences and consequences of the COVID-19 pandemic took place. The first supplemental survey aimed to retrospectively capture the behavior, attitudes, stresses, health, and socioeconomic changes during the first wave of the COVID-19 pandemic from March 2020 through the first relaxations of the lockdown measures. The second supplemental survey aimed to assess current behaviors, attitudes, stresses, health, and socioeconomic changes during the COVID-19 pandemic. The third supplemental COVID-19 survey aimed to capture current attitudes, stresses, health, and socioeconomic changes due to the COVID-19 pandemic.<br>In the following, 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
1.2 Intelligence
- 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; children of twins: competence rating
1.7 Self-efficacy
- General self-efficacy
1.8 Self-esteem
- General self-esteem
1.9 Self-regulation
- Consistency of interest, self-control
- Gummy bear test
1.10 Personality
- Neuroticism, extraversion, openness, agreeableness, conscientiousness

2. Career and labor market attainment
2.1 Employment status
- Current employment status/changes regarding employment
2.2 Education
- 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
- Migration
3.2 Discrimination
- 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
- Loneliness
3.5 Political participation
- Interest in politics, political preferences, voting behavior
3.6 Religion
- Religious affiliation, church attendance, religiosity/spirituality
3.7 Cultural capital
- cultural participation, reading, clasical 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 (also children of twins), leisure time, school, romantic relationship, friendships, income)
- Satisfaction with sibling relationship
- Optimism
4.2 Burden and stress
- frequency of arguments with partner or parents
- Stress regulation and coping
- interfamiliar and extrafamiliar: subjective evaluation - stress symptoms
4.3 Life Goals: importance and progress
4.4 Sensory-processing sensitivity
4.5 Bullying
- in the childhood and adolescence, at work

5. Physical and psychological health
5.1 Subjective health
5.2 Objective health and diagnosis
- Measures of height and weight child´s medical records
- Depression
- Pregnancy (also children of twins)
- Puberty
5.3 Health-related behavior
- alcohol consumption, smoking, medication, medical checkups
- sexual behavior

6. Deviant behavior and behavioral problems
6.1 Internalizing
- Emotional symptoms, problems with peers, social difficulties
6.2 Externalizing
- 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. Demographics
7.1 Information on household
- Household questionnaire (persons in the household, household grid, type of dwelling, income), information on assets

8. Environment
8.1 Activities with children
- Occurrence and frequency of e.g., singing and making music together; story time; doing sports; cultural activities
8.2 Nursery
- Detailed information on nursery and daycare institutions
8.3 Grand-parents
- 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)
8.6 Involvement
- 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
9.1 Zygosity
- 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.