Survey methodology

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Our studies are at the forefront of best practice internationally in a range of different areas relating to longitudinal survey methods, and are informed by the most up-to-date evidence available. We share our learning through publications, conferences presentations and our networks. We work closely with the UK survey agencies who carry out the data collection for our studies.

Our survey methods work is led by Dr Lisa Calderwood, and we have an internal Survey Methodology Research Group. Our research interests and outputs are closely aligned to the practical methodological issues that we address though the design and implementation of our studies.

We provide advice and consultancy on longitudinal survey methods. Do get in touch to find out more about our survey methods work or if you’d like advice on designing and running longitudinal surveys.

Here you can find out more about our key areas of survey methods research.

Data collection mode

We mainly use face-to-face interviewing to collect data from cohort members. We do this to help maximise response rates, and because some of our studies involve physical measurements, biological samples and direct assessments of cognitive function. We have also used telephone interviewing, and the web, to collect data, sometimes in combination with each other and with face-to-face interviewing.

Web data collection is a particular focus for us. We have used this mode in major sweeps of the National Child Development Study (NCDS), Next Steps and the Millennium Cohort Study (MCS), and we are considering whether to make greater use of the web in our studies, including between major sweeps.

Our research interests are around the implications of mode choice in longitudinal surveys, In particular, we focus on how to make the most effective use of the web, whilst ensuring both data quality and high-participation rates and understanding the impact of mode on measurement.

New technologies and innovations in data collection

We have used new technologies for data collection in the MCS age 14 sweep for the time-use diary. This was mixed-mode using web, Smartphone app and paper.

For the MCS age 7 and age 14 sweeps, and the age 46 sweep of the 1970 British Cohort Study (BCS70), we used a portable activity monitor (or accelerometer) to collect direct measurements of physical activity.

We’re exploring opportunities for embedding new technologies and innovations within planned upcoming sweeps, and enhancing our studies with data collected, actively or passively, between sweeps using remote modes.

While it is certainly the case that there are many opportunities in this area, they are not without their challenges, such as cost, measurement issues and take-up. Our research interests are around how to make optimal use of these new opportunities to provide data for research, while understanding their limitations and overcoming their challenges.

Questionnaire design

There are a number of areas of questionnaire design which are of specific relevance to longitudinal surveys, including event histories, retrospective data collection, and dependent interviewing.

All of our study sweeps make extensive use of dependent interviewing, and recent sweeps of BCS70 (age 42), NCDS (age 55) and Next Steps (age 25) have used visual event-history calendars embedded into the questionnaire instrument. The upcoming sweep of NCDS (age 62) will include a retrospective Life History Questionnaire.

Our research interests are around how to optimally design questionnaires in longitudinal surveys, and the impact of these design choices on measurement.

Record linkage

All of our studies have collected a wide range of consents to link to administrative records.

Our research interests are around how to optimally collect record linkage consents, and which factors determine whether cohort members agree to these permissions.

Response rates and attrition

Response maximisation is crucial for delivering accurate and robust data, and making sure our studies remain representative over time. We use a range of best practice approaches to response maximisation, and make use of para-data for case prioritisation during fieldwork.

Our research interests are around how to optimally manage the trade-offs between survey costs, response rates and sample representativeness, and how to improve survey design to maximise response rates.

Participant tracking and engagement

Keeping track of cohort members who move, and keeping them in engaged over time, is a crucial aim for all of our studies. We use a range of best practice approaches, including using administrative data and social media for participant tracking and engagement.

Our research interests are around how to optimally track and engage participants in our studies.

Combining social and biomedical data collection

Collecting objective measurements of health, often referred to as ‘biomeasures’, is an important feature of our studies. This data enables researchers to generate new insights into our understanding of the interplay between social and biological factors in explaining human behaviour.

There are different models for combining social and biomedical data in large-scale surveys, including clinic and home visit based approaches. Our studies have used interviewers to collect biomeasures on MCS, and nurse interviewers on BCS70 and NCDS.

Our research interests are around how to optimally include biomedical data collection in longitudinal surveys, and the impact of these different approaches on cost, response rates and measurement.

Surveying children and young people

Our work on the MCS has pushed forward best practice in surveying children and young people. This covers questionnaire design, engagement and ethical approaches.

Our research interests are around how to optimally design surveys involving children and young people

Research projects and outputs


Children’s time-use diaries: promoting research, sharing best practice and evaluating innovations in data collection internationally

24 October 2018 This research project aimed to optimise the design and coverage of the MCS age 14 time-use diary so as to maximise benefit to the research community and minimise non-response due to respondent burden.

A misspent youth? How new technology is shedding light on what teenagers do all day

24 October 2018 18 May 2018 To coincide with the Millennium Cohort Study time use diary and accelerometer data release, CLS Survey Manager, Dr Emily Gilbert, discusses how the use of new technology has enabled us to gain new insights into the lives of the millennial generation.

Linking cohort study data to administrative records: the challenges of consent and coverage

24 October 2018 Using linked data from the Millennium Cohort Study (MCS), this research project examined patterns of non-consent and non-coverage, and identifies weighting and imputation techniques that can adjust for biases.

We all see the value in combining social and biomedical data collection, so let’s ensure we can do it effectively

24 October 2018

We need to share expertise and learning across the social and biomedical sciences – on both scientific opportunities and operational challenges – to unlock the huge potential of combining social and biomedical data, argues Matt Brown.

Featured scientific publications

Thornby, M., Calderwood, L., Kotecha, M., Beninger, K., & Gaia, A. (2018).
Collecting Multiple Data Linkage Consents in a Mixed-mode Survey: Evidence from a large-scale longitudinal study in the UK.
Survey Methods: Insights from the Field, 1-14.
Read the full paper
Chatzitheochari, S., Fisher, K., Gilbert, E., Calderwood, L., Huskinson, T., Cleary, A., & Gershuny, J. (2017).
Using New Technologies for Time Diary Data Collection: Instrument Design and Data Quality Findings from a Mixed Mode Pilot Survey.
Social Indicators Research, Volume 137, Issue 1, p379-390
Read the full paper
Gilbert, E, Conolly, A, Tietz, S, Calderwood, L, Rose, N (2017).
Measuring young people's physical activity using accelerometers in the UK Millennium Cohort Study
CLS working paper 2017/15. London: Centre for Longitudinal Studies
Read the full paper
Wiggins, R.D., Brown, M. and Ploubidis, G. (2017).
A measurement evaluation of a six item measure of quality of life (CASP6) across different modes of data collection in the 1958 National Child Development Survey (NCDS) Age 55 years.
CLS working paper 2017/2. London: Centre for Longitudinal Studies.
Read the full paper
Contact us

Centre for Longitudinal Studies
UCL Social Research Institute

20 Bedford Way
London WC1H 0AL


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