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Sub-brand to go here. Survey design issues and child outcome measures in the Millennium Cohort Study. Lisa Calderwood Senior Survey Manager Centre for Longitudinal Studies. CLS is an ESRC Resource Centre based at the Institute of Education. Outline of presentation.
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Sub-brand to go here Survey design issues and child outcome measures in the Millennium Cohort Study Lisa Calderwood Senior Survey Manager Centre for Longitudinal Studies CLS is an ESRC Resource Centre based at the Institute of Education
Outline of presentation • Introduction to the Millennium Cohort Study • Methodological and design issues • Child outcome measures
Millennium Cohort Study (MCS) • Longitudinal birth cohort study following over 19,000 children born in the UK in 2000/2001 • Four sweeps so far at 9 months, 3 years, 5 years and 7 years, next planned for 11 years • Funded by UK Economic and Social Research Council (ESRC) and UK government departments • Over sampled places in Scotland, Wales and Northern Ireland, areas with high child poverty and in England areas with higher minority ethnic populations • One of four British Birth Cohort Studies
British Birth Cohort Studies • MCS: the first national birth cohort study for 30 years • Previous UK/GB National Studies: 1946: MRC National Survey of Health & Development 1958: National Child Development Study (NCDS) 1970: 1970 British Birth Cohort Study • 1958, 1970 & MCS based at CLS
Objectives of MCS To chart the initial conditions of the social, economic and health advantages and disadvantages facing new children in the new century and their consequences To capture information for the future To compare patterns of development with other cohorts To collect information on previously neglected topics, such as father’s involvement and child care To investigate the wider social ecology of the family, including community and services, splicing in geo-coded data
MCS Study Design Cohort born over a 12 month period Includes children in England, Scotland, Wales and Northern Ireland Geographically clustered by electoral ward Over represents children from different ethnic groups and those in deprived areas
MCS Sample Design • Stage 1: Selection of electoral wards (398) • Ethnic • Disadvantaged • Advantaged • Stage 2: Selection of families (27201) • From child benefit records held by Department of Work and Pensions • 18,552 families recruited at 9 months + 692 families at 3 years = 19,244 families
MCS Sponsors • UK Economic & Social Research Council • ONS consortium of UK Government Departments: • Office for National Statistics • Department for Children, Schools and Families • Department for Work and Pensions • Department of Health • Welsh Assembly Government • Scottish Government • NI Executive • SureStart - National Evaluation in England • Children’s Fund - National Evaluation in England
Content of MCS Parent Interviews Pregnancy and Child Birth Child Development and Behaviour Education and Childcare Child Health Family Demographics, Family Relationships and Parenting Parental Health Parental Employment, Education and Income Attitudes Social and Community Context
MCS Add on studies • Collection of bio-markers • Oral fluid sample for exposure to infections at age 3 • Shed milk teeth for lead from age 6 upwards • Saliva samples for DNA from mothers, fathers and children at age 11? • Physical activity monitoring at age 7 • Sub-studies • Mothers who had assisted fertility treatment • Nursery observations at age 3 • Methodological studies • Predicting and preventing non-response
Theoretical framework • Groves at al. (1989): Total Survey Error
Outline of section on methodology • Non-response • Measurement • Surveying children
Non-response in longitudinal surveys • Different sources of attrition: location, contact and co-operation e.g. Lepkowski and Couper (2002), Lynn et al. (2002) • Many longitudinal surveys have developed highly successful strategies to minimise attrition through failure to locate and failure to co-operate
Response rates at MCS1(Baseline) • Response rate at baseline sweep was 72% • Response rate differed by country: • lowest in Northern Ireland (66%) • Response rate differed by ward type: • lowest in ethnic areas (66%) • lower in disadvantaged than advantaged (72% vs. 76% in England)
Study design Division of responsibilities Between CLS and Agency Instrument Design Data documentation Science Instrument realisation Data processing Data collection Calderwood, 2009
Fieldwork procedures: securing informed consent • Advance letter and general information leaflet • Additional leaflets with more detailed information e.g. child elements, teacher survey, data linkage • Information leaflet for child introduced at age 7 • Written consent from parents for own and child’s participation, teacher survey and data linkage • Verbal assent from child at age 11
Fieldwork procedures:response maximisation • Telephone contact (for some) at MCS3 and MCS4 • Minimum requirements for call attempts • Refusal conversion • Multiple visits and interviewer flexibility
Interviewer tracking procedures • Multiple attempts to contact sample members, current occupiers, neighbours and stable contacts through personal visits, telephone, mail, email, text
Cohort maintenance procedures used on MCS • Send feedback on results every year • Update contact information every year • Encourage families to contact us with change of address i.e. Freephone number, email address and website • Office-based tracking (and through admin data) for those known to have moved • Additional/bespoke mailings for certain groups e.g. refusals, emigrants
Cohort maintenance procedures used on MCS • Annual updating of contact information • Reply-slip pre-printed with full contact details i.e. Home address and phone, names of parents and child, parent’s phone numbers (mobile and work), email address and ‘stable contacts’ • Proportion with different types of contact information
Tracking procedures used on MCS • Office-based tracking • Attempt to contact sample members, current occupiers and stable contacts through telephone, mail, email and text • Use electoral and phone records and postal directories which are available publicly, centrally and electronically • Attempt tracking through administrative data sources
Residential mobility, trackingand non-response on MCS • Conditional on successful location, mobile families in MCS are no less likely to co-operate at next sweep than non-mobile families (Plewis et al., 2008, Calderwood, 2009) • Tracking methods used on MCS are successful: over 90% of mobile families are successfully located at next sweep(Calderwood, 2009) • Comparable to other major longitudinal studies (Couper and Ofstedal, 2009)
Measurement in longitudinal surveys • Measurement of change and the contribution of dependent interviewing e.g. Moore et al., 2009, Jackle, 2009 • Panel conditioning e.g. Sturgis et al. 2009 • Mode changes between sweeps e.g. Dillman, 2009 • Uses of administrative data e.g. Calderwood et al, 2009 • Role of interviewers e.g. Lynn, 2008
Conducting longitudinal survey research with children • Data collection mode – use of web surveys? • Contact and communication – email, text, web including social networking sites • Ethical and legal issues relating to consent to participate (and link to administrative data) • Giving children a voice – advisory/participation panel?
Outline of section on child outcome measures • Cognitive development • Behavioural development • Physical growth and development
Cognitive Assessment at 3 • Bracken School Readiness Assessment • The sub-tests administered evaluates 88 concepts relating to: • Colours - represents both primary colours and basic colour terms. • Letters- measures knowledge of both upper- and lower-case letters. • Numbers/Counting - measures recognition of single- and double-digit numbers and samples the ability to assign a number value to a set of objects. • Sizes - includes concepts that describe one, two, and three dimensions. • Comparisons - measures ability to match and/or differentiate objects based on one or more of their salient characteristics. • Shapes - includes one-, two-, and three-dimensional shapes. The one-dimensional category includes linear shapes; two-dimensional shapes are represented by concepts such as the circle, square, and triangle; and three-dimensional shapes include concepts such as the cube and pyramid.
Cognitive Assessment at 3 and 5 • BAS Naming Vocabulary • Selected from British Ability Scales (BAS) Used at age 3 at age 5 • A verbal scale for children aged 2 years 6 months to 7 years 11 months. It assesses the spoken vocabulary of young children. • The interviewer shows a booklet of coloured pictures of objects which the child is shown one at a time and asked to name. • Measures expressive language ability, and successful performance depends on the child’s previous development of a vocabulary of nouns. The items require the child to recall words from long-term memory rather than to recognise or understand the meaning of words or sentences.
Practical problems in administering assessment • Anyone else present during Assessment? • If so who – mother, father, children, other? • Effect on child's performance of this presence. • What was child’s energy level during Assessment? • Language • Vocab cannot be assessed if child speaks another language • Child may be too shy, or too young at 3 to attempt the assessment • Ca 2500 missing cases, ca 16% at age 3
Cognitive Scores: findings • Both BAS and Bracken showed marked patterning by socio economic variables, gender, and ( at age 3) ethnic group • Although they cannot are not repeated, at all for Bracken, and beyond age 5 for BAS Naming Vocabulary, they are also highly predictive of later cognitive and school outcomes, known so far to age 7 • As age-appropriate instruments change it is a challenge to monitor a child’s progress longitudinally • Note also that more of the children who were ‘too slow’ to do cognitive assessments at age 3 start to be able to do so. • Need to adjust for age at interview.
