The Centre for Longitudinal Studies (CLS) at the Institute of Education, University of London (UK) is seeking tenders from survey research agencies to carry out the instrument development, data collection and initial data processing for the age 55 follow-up. The National Child Development Study (NCDS) follows the lives of 17 000 people born in England, Scotland and Wales in a single week of 1958. Also known as the 1958 Birth Cohort Study, it collects information on physical and educational development, economic circumstances, employment, family life, health behaviour, wellbeing, social participation and attitudes. The study is core-funded by the Economic and Social Research Council. Since the birth survey in 1958, there have been eight further follow-ups at ages 7, 11, 16, 23, 33, 42, 46 and 50 and in 2003 (at age 45) 9 000 cohort members also participated in a ‘bio-medical’ follow-up. The next follow-up will take place in 2013 when cohort members will be aged 55. Data will be collected using a sequential mixed-mode approach using computer assisted web and telephone interviewing (CAWI and CATI). Cohort members will initially be invited to take part in a 25 minute computer assisted web interview (CAWI) and those not responding online will be contacted by telephone and invited to complete a computer assisted telephone interview (CATI). The CAWI and CATI surveys will use the same questionnaire. Prior follow-ups have typically been conducted face-to-face although the age 46 survey in 2004 was conducted via telephone. The age 55 follow-up will be the first time that cohort members have been invited to participate in a web-survey. It is anticipated that around 11 700 cohort members will be invited to participate. Fieldwork must take place between April 2013 and November 2013.

The survey research agency will be required to:

— Work closely with CLS to design and develop the data collection instruments. The agency will be responsible for the production of all instruments including all CAI programming required,

— The agency will be required to conduct the CAWI survey,

— Supply and train telephone interviewers to conduct the CATI interviews,

— Monitor and oversee the CAWI and CATI surveys to ensure that data collection is carried out on schedule and to a high standard,

— Carry out initial data processing i.e. coding, editing and data checking prior to delivering the data to CLS and provide full documentation of the data collection instruments.