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The harmonisation of longitudinal data: a case study using data from cohort studies in The Netherlands and the United Kingdom


This paper presents a case study of the challenges and requirements associated with harmonising data from two independently-conceived datasets from The Netherlands and the United Kingdom: the Longitudinal Aging Study Amsterdam (LASA) and the Nottingham Longitudinal Study of Activity and Ageing (NLSAA). The objectives were to create equivalent samples and variables, and to identify the methodological differences that affect the comparability of the samples. Data are available from the two studies' 1992–93 surveys for respondents born during 1908–20, and the common data set had 1,768 records and enabled the creation of 26 harmonised variables in the following domains: demographic composition and personal finances, physical health, mental health and loneliness, contacts with health services, physical activity, religious attendance and pet ownership. The ways in which the methodological differences between the two studies and their different selective attrition might lead to sample differences were carefully considered. It was concluded that the challenges of conducting cross-national comparative research using independent datasets include differences in sampling, study design, measurement instruments, response rates and selective attrition. To reach conclusions from any comparative study about substantive socio-cultural differences, these challenges must first be identified and addressed.

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Address for correspondence: Peter Bath, Centre for Health Information Management Research, University of Sheffield, Regent Court, 211 Portobello Street, Sheffield S1 4DP, UK E-mail:
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A. Bedford , G. A. Foulds and B. F. Sheffield 1976. A new personal disturbance scale: DSSI/SAD. British Journal of Social and Clinical Psychology, 15, 4, 387–94.

M. A. Casado-Díaz , C. Kaiser and A. M. Warnes 2004. Northern European retired residents in eight southern European areas: characteristics, motivations and adjustment. Ageing & Society, 24, 3, 353–81.

P. J. Curran 2009. The seemingly quixotic pursuit of a cumulative psychological science: introduction to a special issue. Psychological Methods, 14, 2, 7780.

P. J. Curran and A. M. Husong 2009. Integrative data analysis: the simultaneous analysis of multiple data sets. Psychological Methods, 14, 2, 81100.

D. J. H. Deeg 2002. Attrition in longitudinal population studies: does it affect the generalizability of the findings? An introduction to the series. Journal of Clinical Epidemiology, 55, 3, 213–5.

D. J. H. Deeg , T. G. van Tilburg , J. H. Smit and E. D. de Leeuw 2002. Attrition in the Longitudinal Aging Study Amsterdam: the effect of differential inclusion in side studies. Journal of Clinical Epidemiology, 55, 4, 319–28.

R. Fleishman and A. Shmueli 1984. Patterns of informal social support of the elderly: an international comparison. The Gerontologist, 24, 3, 303–12.

M. Folstein , S. Folstein and P. R. McHugh 1975. Mini-Mental State: a practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research, 12, 3, 189–98.

S. M. Hofer and A. M. Piccinin 2009. Integrative data analysis through coordination of measurement and analysis protocol across independent longitudinal studies. Psychological Methods, 14, 2, 150–64.

N. Minicuci , M. Noale , C. Bardage , T. Blumstein , D. J. H. Deeg , J. Gindin , M. Jylha , S. Nikula , A. Otero , N. L. Pedersen , S. M. F. Pluijm , M. V. Zunzunegui and S. Maggi 2003. Cross-national determinants of quality of life from six longitudinal studies on aging: the CLESA Project. Aging Clinical and Experimental Research, 15, 3, 187202.

K. Morgan 1998. The Nottingham Longitudinal Study of Activity and Ageing: a methodological overview. Age and Ageing, 27, Supplement 3, 511.

K. Morgan , H. M. Dallosso , T. Arie , E. J. Byrne , R. Jones and J. Waite 1987. Mental health and psychological well-being among the old and very old living at home. British Journal of Psychiatry, 150, 6, 801–7.

S. Nikula , M. Jylha , C. Bardage , D. J. H. Deeg , J. Gindin , N. Minicuci , S. M. F. Pluijm and A. Rodriguez-Laso 2003. Are IADLs comparable across countries? Sociodemographic associates of harmonized IADL measures. Aging Clinical and Experimental Research, 15, 6, 451–9.

L. S. Radloff 1977. The CES-D scale: a self-report depression scale for research in the general population. Applied Psychological Measurement, 1, 3, 385401.

A. S. Zigmund and R. P. Snaith 1983. The Hospital Anxiety and Depression Scale. Acta Psychiatrica Scandinavica 67, 6, 361–70.

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Ageing & Society
  • ISSN: 0144-686X
  • EISSN: 1469-1779
  • URL: /core/journals/ageing-and-society
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