Summary: studies at different ages

This section provides broad summaries of the TEDS studies carried out at different twin ages: coverage of twin birth cohorts, and types of measure collected at each age.

Cohorts contacted in each study

This table shows broadly which TEDS cohorts were involved in each of the main data collections. In each table cell, "y" means yes, the data were collected. There is considerable variation in the Ns at each data collection - see the data returns page for more detail. An asterisk (*) indicates some exceptions within studies, which are explained in notes below the table. Follow links (above) to each main study's measures page for full details.

Twin year of birth 1994 1995 1996
Twin birth date ranges Jan-94 to Apr-94 May-94 to Aug-94 Sep-94 to Dec-94 Jan-95 to Apr-95 May-95 to Aug-95 Sep-95 to Dec-95 Jan-96 to Apr-96 May-96 to Aug-96 Sep-96 to Dec-96
Twin age Reported by Collection type cohort 1 cohort 2 cohort 3 cohort 4
1.5 parent booklet y y y y y y y y y
2 parent booklets y y y y y y - - -
3 parent booklets y y y y y y - - -
4 parent booklets y y y y y y y y y
4.5 parent, twins home visit * y y y y y y y y y
7 parent, teachers questionnaires y y y y y y y y y
twins phone tests * y y y y y y - - -
8 parent questionnaire y y y y y y y y y
9 parent, twins, teachers booklets y y y y y - - - -
10 parent, twins web tests y y y y y - - - -
teachers questionnaire y y y y y - - - -
12 parent, twins, teachers questionnaires y y y y y y y y y
twins web & phone tests y y y y y y y y y
14 twins web tests y y y y y y y y y
parent, twins questionnaires * y y y y y y y y y
teachers questionnaire * y y - - - - - - -
16 parent, twins questionnaires y y y y y y y y y
twins some qnr measures * - - y y y y y y y
twins some qnr measures * y y - - - - - - -
parent, twins web tests and qnrs y y y y y - - - -
18+ parent, twins questionnaire * y y y y y y y y y
twins perception web tests y y - - - - - - -
twins spatial web tests y y y y y - - - -
twins FFMP web tests - - - - - y y y -
21 parent, twins questionnaires y y y y y y y y y

* Exceptions exist where certain measures were not collected across all the cohorts shown for a given study. The main exceptions are as follows.

Types of measures collected in each study

The table below shows, in broad terms, some of the main categories of measures that were collected in each of the main TEDS studies. Note that this is a simplification because not all measures are easy to categorise in this way. For further details see the study measure pages (links at the top of this page) and also the sections following on this page.

As in the table above, "y" in a table cell means that the given type of measure was collected at the given age.

Twin age Reported by Collection type Twin behaviour measures Twin language reports or tests Twin general cognitive tests Other twin tests Twin educational achievement Home environment measures School environment measures SES Twin health General family background
1.5parentbooklet-------yyy
2parentbookletyyy------y
3parentbookletyyy--y--yy
4parentbookletyyy--y--yy
4.5twinshome visityyy--y----
7parentquestionnairey----y-yyy
teachersquestionnairey---y-y---
twinsphone tests-yy-------
8parentquestionnairey---------
9parentquestionnaireyy---yyyyy
teachersquestionnaireyy--y-y---
twinsquestionnairey-y--yy---
10twinsweb tests & qnr-yy--yy---
teachersquestionnaire-y--y-y---
12parentquestionnairesy---y----y
teachersquestionnairey---y-----
twinsquestionnairey-------y-
twinsweb test & qnr, phone test-yyy-yy---
14parentquestionnairesyy--yy----
teachersquestionnairey---y-y---
twinsquestionnairey----y--y-
twinsweb tests--yy------
16parentqnr (paper + web)y------ y-y
twinsqnr (paper + web)y---yy- -yy
 twinsweb tests-yyy--- ---
18+parent, twinsquestionnaire----y-y---
twinsPerception web tests---y------
twinsSpatial web tests---y------
twinsFFMP web tests------- -y-
21parentquestionnairey----y-y--
twinsquestionnairey---yy-yyy

Specific measures used longitudinally

The sections below provide more detailed summaries of specific measures, grouped by type, that have been collected at different ages in TEDS. Under each heading there is a table to show measures, or types of measure, that have been collected repeatedly at different ages.

This is not intended to be an exhaustive list of all measures collected in TEDS. A few measures have had to be omitted: such measures are often short, not published, not repeated across ages, and not easily categorised into the sections below.

Cognitive and language measures

Cognitive tests, and reports of cognitive abilities, have been included in many of the TEDS data collections. The table below groups the cognitive measures into broad types, and shows which measures have been used at which ages. Table cells show brief names of relevant measures. For full details of measures including references, see the study measures pages that are linked at the top of this page.

Twin age Reported by Collection type 'g' composite (general cognive ability) Non-verbal cognitive tests Verbal, language and reading tests Language reports Maths and numerical tests Other types of test
2 parent booklet yes PARCA: Drawing, Matching, Folding, Copying, Brick building, parent report - MCDI: Vocabulary, Word Use, Sentence Complexity - -
3 parent booklet yes PARCA: Drawing, Matching, Odd-one-out, parent report - MCDI: Vocabulary, Word Use, Sentence Complexity.
Communication items.
- -
4 parent booklet yes PARCA: Drawing, Draw-a-man, Odd-one-out, Puzzle, parent report Picture vocabulary MCDI: Vocabulary.
Grammar, Abstract Language, use of numbers.
Literacy and phonology.
Communication items.
- -
4.5 twin in home tests - McCarthy Scales (18 tests) Phonological Awareness, Goldman-Fristoe, Nonword Repetition, Bus Story, Action Picture, British Ability Scales - - -
7 twin phone tests yes McCarthy: Conceptual Grouping.
WISC: Picture Completion
WISC: Vocabulary, Similarities.
TOWRE.
Non-word list matching.
- - -
parent questionnaire - - - Speech difficulties - -
9 twin questionnaire yes CAT3: Shapes, Puzzles. WISC: Vocabulary, General Knowledge. - - -
parent, teacher questionnaires - - - Communications Checklist - -
10 twin web tests yes Ravens Progressive Matrices.
WISC: Picture Completion.
WISC: Vocabulary, General Knowledge.
PIAT.
Author Recognition.
- Maths test -
teacher questionnaire - - - CELF - -
12 twin web tests
(and phone for TOWRE)
yes Ravens Progressive Matrices.
WISC: Picture Completion.
WISC: Vocabulary, General Knowledge.
PIAT.
Author Recognition.
TOWRE.
Figurative Language, Inferences, Listening Grammar.
GOAL. Reading Fluency.
- Maths test Spatial tests: Hidden Shapes, Jigsaws.
Eyes test.
14 twin web tests yes Ravens Progressive Matrices WISC: Vocabulary - - Science test
parent questionnaire - - - Second language acquisition - -
16 twin web tests yes Ravens Progressive Matrices Mill Hill Vocabulary.
Reading Fluency.
Passages Comprehension.
Figurative Language.
- Maths test.
Dot Number Matching, Dot Task, Problem Verification Task, Corsi Tapping Block, Number Line, Reaction Times.
Spatial tests: Hidden Shapes, Jigsaws.
Eyes test.
18+ twin web tests (4 studies) - - - - - Perception tests.
Spatial tests: Bricks, Kings Challenge, Navigation

Education, attainment and school environment

The table below provides a summary of TEDS measurements of educational attainment together with measures relating to special educational needs, learning difficulties, classroom/school environment or education/school more generally. Table cells show brief names or descriptions of relevant measures. For full details of measures including references, see the study measures pages that are linked at the top of this page.

Twin age Reported by Collection type Official UK assessments and qualifications Current reports of National Curriculum ratings Special educational needs, classroom support, learning disabilities Classroom or school environment Other education-related
7 parent questionnaire - - Diagnosed learning difficulties.
SEN and classroom support.
- Twin attendance and feelings about school.
teacher questionnaire - Maths and English ratings Diagnosed learning difficulties.
SEN and classroom support.
- Twin attendance and feelings about school.
8 parent questionnaire - - Diagnosed learning difficulties. - Striking skills
9 parent questionnaire - - Diagnosed learning difficulties.
SEN.
CEQ Motivational perceived ability
teacher questionnaire - Maths, English and Science ratings SEN CEQ.
School type.
Homework.
Motivational perceived ability
twin questionnaire - - - CEQ Motivational perceived ability
10 teacher questionnaire - Maths, English and Science ratings SEN CEQ.
Classroom chaos.
-
twin web questionnaire - - - Maths and reading in school -
12 parent questionnaire - Maths, English and Science ratings from end of year reports - - -
teacher questionnaire - Maths, English and Science ratings SEN - -
twin questionnaires - - - Maths and reading in school (web qnr) Motivational perceived ability
14 parent questionnaire KS3 end-of-key-stage ratings - - - -
teacher questionnaire - Maths, English and Science ratings SEN School type -
twin web - - - Influences on student outcomes Planned educational courses.
Parental attitudes to education.
16 parent and twins questionnaires GCSE and other age 16 exam results - - - Striking skills
twin web - - - Student classroom environment.
PISA: classroom environment, homework, use of school resources, time spent on maths.
Academic self concept.
School engagement.
PISA: attitudes towards school and subjects, maths self-efficacy and interest.
18 parent and twins questionnaires A-level and other post-16 exam results - - School type when doing GCSE Entry to higher education
21 twin questionnaire - - Diagnosed learning difficulties - Highest level of education.
Higher education outcomes.
College student experiences.
Behaviour Measures

The table below summarises the majory categories of behaviour measure that have been represented in repeated data collections in TEDS. Table cells show brief names of relevant measures. For full details of measures including references, see the study measures pages that are linked at the top of this page.

This is followed by a further table of behaviour measures that do not fall into these categories.

Twin age Reported by Collection type General behaviour measures ASD traits Anxiety and Depression traits ADHD and Hyperactivity traits Psychopathy and Aggression traits Victimisation and relationship problems
2 parent booklet Behar - - - - -
3 parent booklet Behar - DSM-IV items ADHD items - -
4 parent booklet Behar, SDQ CHAT DSM-IV items, OCD items ADHD items - -
4.5 tester in home visit Bayley - - - - -
7 parent questionnaire SDQ DSM-IV items DSM-IV and other anxiety items ADHD items APSD -
teacher questionnaire SDQ DSM-IV items DSM-IV and other anxiety items ADHD items APSD -
8 parent questionnaire - CAST - Conners - RPQ
9 parent questionnaire SDQ CAST DSM-IV and other anxiety items - APSD,
reactive and proactive aggression,
ODD items
-
teacher questionnaire SDQ CAST - - APSD,
reactive and proactive aggression,
ODD items
-
twin questionnaire SDQ CAST - - ODD items -
12 parent questionnaire SDQ CAST MFQ Conners APSD -
teacher questionnaire SDQ CAST - - APSD -
twin questionnaire SDQ - MFQ - - Peer victimisation
14 parent questionnaire - AQ - Conners APSD Peer victimisation
teacher questionnaire - - - Conners APSD Peer victimisation
twin questionnaire - - - Conners - Peer victimisation
16 parent questionnaire SDQ AQ ARBQ, MFQ Conners ICUT -
twin questionnaire SDQ AQ CASI, MFQ SWAN ICUT, Delinquency Peer victimisation (web qnr)
21 parent questionnaire SDQ - - Conners - -
twin questionnaire SDQ - MFQ,
General Anxiety
Conners BAQ,
Antisocial Behaviour,
Criminality
Peer victimisation and perpetration,
Peer pressure,
Online bullying,
Intimate partner violence,
Childhood experiences

Other behaviour measures that do not obviously fall into the categories above, and that have not been used more than once or twice in TEDS data collections, are listed below.

Broad category Names of measures TEDS data collections
Gender Gender role behaviour Age 3 (parent),
Age 4 (parent)
Wellbeing SHS, BMSLSS Age 16 (twin web and twin paper)
Hopefulness, Gratitude, Curiosity, Grit, Optimism Age 16 (twin web)
Trust, Meaning in Life, Basic Psychological Needs, Materialistic Values Age 16 (twin paper questionnaire)
Miscellaneous Highly Sensitive Child, Mindful Attention Awareness Scale Age 16 (twin)
Psychosis traits SANS Age 16 (parent),
Age 21 (parent)
Paranoid checklist, CAPS Age 16 (twin),
Age 21 (twin)
TEPS, Grandiosity, Introvertive Anhedonia, Cognitive Disorganisation, Distress, PLIKS, Hypomania Checklist Age 16 (twin)
Personality Big 5 Age 16 (twin web),
Age 21 (twin)
Opinions and views BSA Environment, BSA Democracy and Government, Perceptions of heritability, Centrality of Religion Scale, Attitudes towards marriage, Life Role Salience Age 21 (twin)
Emerging adulthood Goals, Purpose in Life, Self Control, Future consequences, Volunteering, CLAS (love and relationships, community, finances), Hassles, Ambition, Attitudes to Money, Financial Products, Internet Dating Age 21 (twin)
Risk-taking Age 21 (parent, twin)
Home environment and family background

The table below summarises measures related to home environment, family background, and parent-specific or family-specific measures generally. Table cells show brief names or descriptions of relevant measures. For full details of measures including references, see the study measures pages that are linked at the top of this page.

Twin health-related measures/items are listed separately in the section below, so are not included in this table.

Twin age Reported by Collection type Home environment measures Other twin background measures Parent-specific measures including SES General family background and family history
1.5 parent booklet Dressing the twins.
Care of twins.
Zygosity.
Ethnic origin.
Language spoken.
Handedness.
Respondent and partner: SES (educational level, employment), marital status and relationships to twins Siblings of twins.
2 parent booklet - - - Family events including illness, job changes, new siblings, marital status
3 parent booklet Chaos at home.
Parental feelings and discipline.
HOME: twin play, parents talking to twins.
Dressing the twins.
Care of twins.
Zygosity.
Handedness.
Maternal postnatal depression.
Maternal diabetes.
Parent height and weight.
Family events including illness, job changes, new siblings, marital status
4 parent booklet Chaos at home.
Parental feelings and discipline.
HOME: twin play, parents talking to twins.
Dressing the twins.
Care of twins.
Zygosity.
Handedness.
Maternal postnatal depression.
Parent height and weight.
Family history of medical problems.
Family events including illness, job changes, new siblings, marital status.
4.5 parent questionnaire Twin play and toys - Parent vocabulary test -
tester post-visit ratings Home observations. Parent-child interactions. - - -
7 parent questionnaire Parental feelings and discipline. - Respondent and partner: SES (educational level, employment), marital status and relationship to twins.
Changes to household finances.
Life events checklist.
9 parent questionnaire Chaos at home.
Parental feelings and discipline.
General home environment including parental attitudes to education, homework routines, reading/books, TV.
- SES: household income.
Changes to household finances.
Respondent and partner: marital status and relationship to twins.
Family history of language delays.
Life events checklist.
Other adults living in the home.
twin questionnaire Chaos at home.
Parental feelings and discipline.
General home environment including parental attitudes to education, homework routines, reading/books, TV.
- - -
10 parent web qnr - - Parent reading and maths abilities -
twin web qnr General home environment including homework routines, reading/books, TV. - - -
12 parent booklet Chaos at home.
Parental feelings and discipline.
- Parent adult literacy -
twin booklet Chaos at home.
Parental feelings and discipline.
- - -
twin web qnr General home environment including homework routines, reading/books, TV. - - -
14 parent questionnaire Chaos at home.
Parental feelings and discipline.
- - -
twin questionnaire Chaos at home.
Parental feelings and discipline.
VIP scale.
Parental attitudes to education.
Extra-curricular activities - -
16 parent booklet Paranoid parenting - - Coddington life events.
Family history of schizophrenia and bipolar.
parent web qnr - - SES: maternal and paternal education and employment levels; household income -
twin booklet - Handedness - Coddington life events
twin web qnr Chaos at home.
Parental discipline.
Parental monitoring and control.
Screen time.
Use of social networks.
Peer attachment.
- -
18 parent, twins questionnaire - Current status and living arrangements - -
twins FFMP web tests - Preferences for food, fashion and music - -
21 parent questionnaire Parental feelings Current status and living arrangements SES: maternal and paternal education and employment levels; household income -
twin questionnaire Chaos at home Twin SES: educational level, employment and apprenticeship, benefits.
Current status and living arrangements.
Relationship status.
Media use and attitudes.
PRIUSS.
Extra curricular activities.
- Coddington life events.
Contact and relationships with mother and father.
Twin health

Many TEDS data collections have included questions about twin health. Most of these have been one-off measures, not repeated at other ages (with a few exceptions like height/weight and puberty). Where a health issue was raised at several ages (for example hearing or asthma), generally the question(s) were customised at each age and not the same measure repeated. Often the questions were devised by TEDS researchers or collaborators and were not part of named measures. Sometimes there was just a single question (yes/no for ADHD, for example). Hence, the table below is not a list of measures as such, but is rather a list of twin medical or health-related issues that have been addressed at various ages.

In the table below, unless otherwise stated the questions were part of parent-reported questionnaires.

Twin health-related issue or medical problem Ages (parent booklet report unless otherwise stated)
Twin height and weight Parent report: 1.5 (birth), 3, 4, 7. Twin report: 12, 14, 16 (web), 21.
Puberty (PDS) Twin report: 12, 14, 16 (web)
Pregnancy, birth, perinatal problems 1.5
Breast feeding, infant feeding 1.5, 3
Parental attitudes to twin diet 3, 4
Diet and food preferences Twin report: 18+ (FFMP web), 21 (dietary requirements, REAP healthy eating)
Eating disorders Twin report: 16 (EDDS), 21 (diagnoses, symptoms)
Handedness Parent report: 1.5, 3, 4. Twin report: 16.
Potty training, wetting and soiling 3, 4, 7
Bed time and sleeping patterns 1.5, 3, 4
Sleep problems Twin report: 16 (PSQI, Insomnia Severity), 21 (sleep quality)
GP visits and hospital events Parent report: 1.5, 3, 4, 7. Twin report: 21.
Hearing problems 1.5, 3, 4, 7, 9
Speech problems 1.5, 7
Eyesight problems Parent report: 1.5, 3, 4, 9. Twin report: 16
Asthma 3, 4, 7, 16
Allergies Parent report: 4, 7, 9. Twin report: 18+ (FFMP web), 21.
Eczema and skin problems 3, 4, 7, 9
Fits or seizures 1.5, 3, 4, 7
Tics and twitches 7
Meningitis 4
Diabetes 3, 4
General aches and pains 3, 4, 7
ADHD diagnosis 7, 8, 9
ASD diagnosis 7, 8, 9
Miscellaneous other medical conditions 1.5, 7, 8, 9
Miscellaneous other learning difficulties 3, 4, 7, 8, 9
Mental health: diagnoses and treatment Twin report: 21
Alcohol, smoking, cannabis and other drugs Twin report: 16, 21
Sexual orientation, behaviour and experiences, STDs Twin report: 21
Self harm Twin report: 21
Health economics: day to day difficulties,
use of professional resources
Twin report: 21
Exercise and sports Twin report: 21
Pregnancy and children Parent and twin report: 21