This Guide contains information about Australian primary health care longitudinal studies, definitions of longitudinal studies, its disadvantages and advantages, information for those wanting to conduct a longitudinal study as well as information on how to access the databases and findings of such studies.
Longitudinal studies provide data about the same individual at different points in time allowing the researcher to track change at the
There are a number of different types of longitudinal studies, including:
- Individual level panel surveys, where samples of individuals are tracked and interviewed.
- Household panel surveys, where individuals are followed within the context of the households where they live, and information is normally collected about the whole household at each wave.
- Cohort studies, where samples from a particular age range are followed to explore their different trajectories as they age.
- Record linkage studies, administrative or census data are linked across time.
This type of research examines whether those with a particular exposure develop the outcome of interest at a different rate to those without that exposure. Longitudinal/cohort studies allow investigation of causation of the outcome of interest, and provide the most direct measurement of risk of the outcome. Australian Institute of Health and Welfare 2015
Longitudinal studies are unique in their ability to provide useful data about individual change. This type of study also allows for flexibility, meaning the focus of the study can be shifted whilst data is being collected.
One of the biggest disadvantages to using longitudinal studies is the time factor. This type of study is time consuming, which affects cohort retention and the ability to maintain a committed research team. It also means that these types of studies are costly and the financial burden is one of the biggest challenges facing longitudinal studies.
Australian Institute of Health and Welfare: Logie H, Hogan R & Peut A. (2004). Longitudinal studies of ageing: Implications for future studies,. AIHW cat. no. AGE 42. Canberra: AIHW.
Gregory A, Armstong R, Grassi T, Gaut B, Weyden M. (2008). On our selection: Australian longitudinal research studies. Medical Journal of Australia, 189(11), 650–657.
Van Weel C. (2005). Longitudinal Research and data collection in primary care. Annals of Family Medicine, 3(1), 546–51.
Najman JM, Bor W, O'Callaghan M, Williams GM, Aird R, Shuttlewood G. (2005). Cohort profile: The Mater-University of Queensland study of pregnancy (MUSP). International Journal of Epidemiology, 34, 992–997.
The Clinical Practice Research Datalink (CPRD)
This is the world's largest computerised database of anonymised longitudinal medical records from primary care that is linked with other healthcare data. To date, it contains data from around 5 million patients from about 625 primary care practices across the UK. Formerly known as the General Practice Research Database (GPRD), the CPRD provides capabilty, products and services accross a number of areas including: Data Services; Interventional research services; and Research services. Media release gov.uk
The General Practice Research Network (GPRN)
This is an Australian longitudinal database involving over 1 000 GPs who supply de-identified prescribing data for more than 3 million patients.
Guide to Australian longitudinal studies FaHCSIA Research and Analysis Branch (2013). [PDF:7.5Mb]
Using longitudinal data
Many studies welcome and encourage the use of their datasets as a resource for further studies.
Researchers can apply to access the data through the relevant pathways set out by the organisations that hold the data. To find out the criteria for access to specific data please view the studies' website and contact the appropriate person.
Analysing the data
There are some great statistical software packages available that can help you analyse the data sourced from longitudinal studies. These include multi-level analysis products like MLwiN and HLM as well as some of the more generic software brands like SPSS, SAS/STAT and Stata. For more information about these software products please view the links provided.
If unsure about how to proceed with data analysis, you may find the following references useful:
- Newsom JT, Jones RN, Hofer SM, (Eds). (2011). Longitudinal data analysis. A practical guide for researchers in aging, health, and social sciences. Routledge Academic.
- Arnau J, Balluerka N, Bono R, Gorostiaga A. (2010). General linear mixed model for analyzing longitudinal data in developmental research. Perceptual and Motor Skills, 110, 547–66.
- Holditch-Davis D, Levy J. (2010). Potential pitfalls in collecting and analyzing longitudinal data from chronically ill populations. Newborn and Infant Nursing Reviews, 10(1), 10–18.
Conducting longitudinal research
Using the Australian Longitudinal Study on Womens Health as a case study, this issue of the International Journal of Multiple Research Approaches is designed as a practical guide to the development and management of longitudinal studies with various articles on topics such as cohort management, data management and dissemination of longitudinal data. In a review by Donath (2008), “This collection of papers is a valuable source of practical information on the main aspects of longitudinal studies".
Loxton D, Byles J, Dobson A, Brown W (Eds). (2007). Conducting Longitudinal Research: Practical lessons from the Australian Longitudinal Study on Women's Health, eContent Management, Maleny, Qld.
Donath S. (2008). Conducting longitudinal research: Practical lessons from the Australian Longitudinal Study on Women's Health - Book Review. Australasian Epidemiologist 15(1), 26.
The majority of longitudinal research tends to use predominantly quantitative research methods. This interesting report discusses qualitative longitudinal approaches:
Molloy D, Woodfield K, Bacon J. (2002). Longitudinal qualitative research approaches in evaluation studies, Working Paper Number 7, Department for Work and Pensions, London. [PDF:132Kb]
Australian longitudinal studies
Australian Child to Adult Development (ACAD) study: Longitudinal study of Behavioural and Emotional Disturbance in people with Intellectual Disability
National, 1990 – Ongoing
Australian Epilepsy Research Register
National, 2006 – Ongoing
The Australian MS Longitudinal Study (AMSLS)
National, 2001 – Ongoing
Australian Longitudinal Study of Ageing (ALSA)
Adelaide, 1992 – Ongoing
The Australian longitudinal study of health and relationships
National, 2005 – 2007
Canberra Longitudinal Study of the Elderly
Canberra, 1990 – 2002
Crossroads Undiagnosed Disease Study
Rural Victoria, 2001 – 2003
The DRUID Study: Diabetes and Related disorders in Urban Indigenous people in the Darwin region
Northern Territory, 2001 – Ongoing (current project January 2012–December 2013)
Footprints in Time - The Longitudinal Study of Indigenous Children (LSIC)
National, 2003 – Ongoing
Growing up in Australia - The Longitudinal Study of Australian Children
National, 2003 – Ongoing
Longitudinal Surveys of Australian Youth (LSAY)
National, 1995 – Ongoing
Participation in cervical screening by Indigenous women in the Northern Territory: a longitudinal study
Northern Territory, 1997 – 2004
The 45 and Up Study
New South Wales, 2008 – Ongoing
AusDiab: The Australian Diabetes, Obesity and Lifestyle Study
National, 1999 – 2005, 12-year follow-up completed in 2012.
The BEACH Project: Bettering the Evaluation And Care of Health
National, 1998 – 2017
The Busselton Health Study
Busselton, WA, 1966 – Ongoing
The Dubbo Study
Dubbo, NSW, 1988 – 2004
The Mater-University of Queensland Study of Pregnancy (MUSP)
Brisbane, 1981 – Ongoing
The Tasmanian Longitudinal Health Study (TAHS)
National, 1968 – Ongoing
Wittenoom cohort studies
Wittenoom, WA, 1974 – Ongoing
Women's Health Australia (WHA): Australian Longitudinal Study on Women's Health (ALSWH)
National, 1995 – Ongoing
If you are involved in an Australian health longitudinal study which does not appear here, please let us know by emailing email@example.com and we will add it to this list.
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Primary Health Care Research & Information Service (2017). PHCRIS Getting Started Guides: Introduction to... Longitudinal studies. From http://www.phcris.org.au/guides/longitudinal_studies.php (Accessed 13 Dec 2017)