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Issue 22 Autumn 1998

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Secondary analysis of qualitative data

Janet Heaton

Janet Heaton is a Research Fellow and a part-time DPhil student in the Social Policy Research Unit, Department of Social Policy and Social Work at the University of York. Her interest in secondary analysis of qualitative data developed through the intersection of these two roles. For her doctoral work she is re-analysing data from studies on which she worked as a primary researcher, focusing on the 'temporal imperatives' which characterise the discourses surrounding contemporary hospital discharge policy and practice.

Although the secondary analysis of quantitative data is a common and generally accepted mode of inquiry, the same cannot be said of qualitative data (Hinds, Vogel and Clarke-Steffen 1997). This Update outlines some of the forms that secondary analysis of qualitative data can take, the key methodological and ethical issues that arise, and how the approach might be further developed.

What is secondary analysis?

Secondary analysis involves the use of existing data, collected for the purposes of a prior study, in order to pursue a research interest which is distinct from that of the original work; this may be a new research question or an alternative perspective on the original question (Hinds, Vogel and Clarke-Steffen 1997, Szabo and Strang 1997). In this respect, secondary analysis differs from systematic reviews and meta-analyses of qualitative studies which aim instead to compile and assess the evidence relating to a common concern or area of practice (Popay, Rogers and Williams 1998). As will be shown below, secondary analysis can involve the use of single or multiple qualitative data sets, as well as mixed qualitative and quantitative data sets. In addition, the approach may either be employed by researchers to re-use their own data or by independent analysts using previously established qualitative data sets.

Despite the fact that thus far secondary analysis of qualitative data has not been widely undertaken, there have been a few reviews of the approach (e.g. Hinds, Vogel and Clarke-Steffen 1997, Thorne 1994). Classification of different types of secondary analysis of qualitative data is not straightforward as there are almost as many types as there are examples. It is made more difficult by the fact that some researchers may not define their work as secondary analysis (Hinds, Vogel and Clarke-Steffen 1997).

These difficulties notwithstanding, forms of secondary analysis are cross-classified in Table 1 according to the focus of the analysis and the nature of the original data used. Examples of work classified in this way will be described; some cells remain empty (cells 1c, 2a and b, 3a and c) because appropriate examples have not yet been identified and it is not known if these forms of secondary analysis have ever been conducted (there are no a priori grounds for excluding them).

Table 1: Forms of secondary analysis

Table 1: Forms of secondary analysis

Additional in-depth analysis: a more intensive focus on a particular finding or aspect than was undertaken as part of the primary work. For example, Szabo and Strang (1997) describe how they used secondary analysis of their previous study on informal carers of relatives with dementia to consider how carers' perceived 'control' enabled them to manage their care giving experience (cell 1a). Bull and Kane (1996) conducted a secondary analysis of two data sets previously collected by the first author, both of which were broadly concerned with elderly people's discharge from hospital to home, to investigate in more depth the nature of the problems encountered by professionals and users (cell 1b). Again using data from two qualitative studies on which they had worked separately, Angst and Deatrick (1996) described how children with chronic illness and their parents are involved in health care decisions (cell 1b). Similarly, Kirschbaum and Knafl (1996) combined data from two studies with which they had been involved, to explore the nature and quality of parent-professional relationships across two different illness situations (cell 1b).

Additional sub-set analysis: a selective focus on a sub-set of the sample from the original study (or studies), sharing characteristics which warrant further analysis. For instance, in their secondary analysis of related quantitative and qualitative data sets about claimants of Invalid Care Allowance, McLaughlin and Ritchie (1994) concentrate on the ex-carers in the original sample in order to describe the socio-economic and psychological legacies of care giving among this group (cell 2c).

New perspective/conceptual focus: the retrospective analysis of the whole or part of a data set from a different perspective, to examine concepts which were not central to the original research. I have adopted this strategy in my ongoing doctoral research which involves re-examining qualitative data relating to people's experiences of hospital discharge in order to explore the temporal organisation of this process and associated aftercare regimes (cell 3b). In addition, although not self-defined as secondary analysis, Bloor and MacIntosh's (1990) study of techniques of client resistance to surveillance drew on two earlier studies that they conducted and provides a further illustration of this approach (cell 3b).

Why do secondary analysis?

There is growing interest in re-using qualitative data, reflected in the establishment of Qualidata by the ESRC. This facilitates the archiving of data from qualitative studies (Corti and Thompson 1998, Hammersley 1997, Corti et al 1995). More generally, limited opportunities for conducting primary research and the costs of qualitative work have prompted researchers to consider maximising use of the data available to them. The advent of software to aid the coding, retrieval and analysis of qualitative data is another development which is likely to facilitate both the archiving and availability of qualitative data for secondary analytic purposes. In these respects, the impetus behind the approach is similar to the one which informed the secondary analysis of quantitative data (Procter 1993).

Various arguments in favour of developing secondary analysis of qualitative studies have been put forward (Hinds, Vogel and Clarke-Steffen 1997, Sandelowski 1997, Szabo and Strang 1997, Thorne 1994). For example, it has been contended that the approach can be used to generate new knowledge, new hypotheses, or support for existing theories; that it reduces the burden placed on respondents by negating the need to recruit further subjects; and that it allows wider use of data from rare or inaccessible respondents.

In addition, it has been suggested that secondary analysis is a more convenient approach for particular researchers, notably students (Szabo and Strang 1997). However, Thorne (1994) argues that where the researcher was not part of the original research team the approach is best only employed by experienced researchers because of the particular difficulties of doing secondary analysis in an independent capacity. It should also be noted that use of the approach does not necessarily preclude the possibility of collecting primary data. This may, for example, be required to obtain additional data or to pursue in a more controlled way the findings emerging from the initial analysis. There may also be a need to consult the primary researcher(s) (assuming that they are available) in order to investigate the circumstances of the original data generation and processing.

Despite the interest in and arguments for developing secondary analysis of qualitative data, the approach has not been widely adopted to date. Furthermore, as was shown above, existing studies have mainly been conducted by researchers re-using their own data rather than by independent analysts using data collected by others. This raises questions about the desirability and feasibility of particular strategies for secondary analysis of qualitative data discussed below.

Methodological and ethical considerations

Before highlighting some of the key practical and ethical issues which have been discussed in the literature, there are two fundamental methodological issues to be considered.

The first is whether secondary analysis of qualitative studies is tenable, given that it is often thought to involve an inter-subjective relationship between the researcher and the researched. In response, it may be argued that even where primary data is gathered via interviews or observation in qualitative studies, there may be more than one researcher involved. Hence within the research team the data still has to be contextualised and interpreted by those who were not present. A more radical response is to argue that the design, conduct and analysis of both qualitative and quantitative research are always contingent upon the contextualisation and interpretation of subjects' situation and responses. Thus, secondary analysis is no more problematic than other forms of empirical inquiry, all of which, at some stage, depend on the researcher's ability to form critical insights based on inter-subjective understanding.

The second issue concerns the problem of where primary analysis stops and secondary analysis starts. Qualitative research is an iterative process and grounded theory in particular requires that questions undergo a process of formulation and refinement over time (Glaser 1992). For primary researchers re-using their own data it may be difficult to determine whether the research is part of the original enquiry or sufficiently new and distinct from it to qualify as secondary analysis. For independent analysts re-using other researchers' data there are also related professional issues about the degree of overlap between their respective work. There is no easy solution to these problems except to say that greater awareness of secondary analysis might enable researchers to more appropriately recognise and define their work as such.

Just as the above issues have received little attention in the literature to date, so the principles of, and guidelines for, the conduct of secondary analysis remain rather ill-defined (Thorne 1994). However, a number of practical and ethical considerations have been highlighted (Hinds, Vogel and Clarke-Steffen 1997, Szabo and Strang 1997, Thorne 1994) and four key issues are summarised below.

  1. Compatibility of the data with secondary analysis: are the data amenable to secondary analysis? This will depend on the 'fit' between the purpose of the analysis and the nature and quality of the original data (Thorne 1994). Scope for additional in-depth analysis will vary depending on the nature of the data; for example, while tightly structured interviews tend to limit the range of responses, designs using semi-structured schedules may produce more rich and varied data. A check for the extent of missing data relevant to the secondary analysis but irrelevant to the original study may also be required; for example, where semi-structured interviews involved the discretionary use of probes. More generally, the quality of original data will also need to be assessed and Hinds, Vogel and Clarke-Steffen (1997, appendix) provide a set of criteria for this task.

  2. Position of the secondary analyst: was the analyst part of the original research team? This will influence the decision over whether to undertake secondary analysis and, if so, the procedures to be followed. Secondary analysts require access to the original data, including tapes and field notes, in order to re-examine the data with the new focus in mind. This is likely to be easier if they were part of the original research team. If not, then ideally they should also be able to consult with the primary researcher(s) in order to assess the quality of the original work and to contextualise the material (rather than rely on field notes alone). Further consultation may also be helpful in terms of cross-checking the results of the secondary analysis. Finally, whether conducting secondary analysis in an independent capacity or not, some form of contractual agreement between the secondary analyst and the primary researcher(s), data archive managers, and colleagues involved in the primary research but not in the secondary analysis may have to be negotiated.

  3. Reporting of original and secondary data analysis: such is the complexity of secondary analysis, that it is particularly important that the study design, methods and issues involved are reported in full. Ideally this should include an outline of the original study and data collection procedures, together with a description of the processes involved in categorising and summarising the data for the secondary analysis, as well as an account of how methodological and ethical considerations were addressed (Thorne 1994).

  4. Ethical issues: how was consent obtained in the original study? Where sensitive data is involved, informed consent cannot be presumed. Given that it is usually not feasible to seek additional consent, a professional judgement may have to be made about whether re-use of the data violates the contract made between subjects and the primary researchers (Hinds, Vogel and Clarke-Steffen 1997). Growing interest in re-using data make it imperative that researchers in general now consider obtaining consent which covers the possibility of secondary analysis as well as the research in hand; this is consistent with professional guidelines on ethical practice (British Sociological Association 1996).

Developing the approach

To see if the potential of secondary analysis can be realised in practice, developmental work still needs to be undertaken. First, there should be a more comprehensive review of the literature on secondary analysis and studies which have explicitly (and perhaps implicitly) used this approach. This could include examination of the methods used, as well as the quality, value and impact of this work. Secondly, further work on the protocols for conducting secondary analysis of qualitative data, particularly with regard to the re-use of other researchers' data should be carried out. Thirdly, there should be greater consideration of the issues involved in the secondary analysis of single, multiple and mixed data sets. Finally, some more specific guidelines are needed for researchers about the ethical issues to be considered when undertaking qualitative work that may be re-used in the future. On this note, it is encouraging that Qualidata are currently working with the ESRC to produce guidelines on collecting and preparing data for archiving and on issues of confidentiality and copyright (Corti and Thompson 1998).


Despite growing interest in the re-use of qualitative data, secondary analysis remains an under-developed and ill-defined approach. Various methodological and ethical considerations pose a challenge for the would-be secondary analyst, particularly those who were not part of the primary research team. Further work to develop this approach is required to see if the potential benefits can actually be realised in practice.


Angst, D.B. and Deatrick, J.A. (1996) 'Involvement in health care decisions: parents and children with chronic illness', Journal of Family Nursing, vol. 2(2): 174-95.

Bloor, M. and MacIntosh, J. (1990) 'Surveillance and concealment: a comparison of client resistance in therapeutic communities and health visiting' in Cunningham-Burley, S. and McKeganey, N.P. (Eds.) Readings in Medical Sociology. London: Routledge.

British Sociological Association (1996) 'Statement of Ethical Practice'.

Bull, M.J. and Kane, R.L. (1996) 'Gaps in discharge planning', Journal of Applied Gerontology, vol. 15(4): 486-500.

Corti, L. and Thompson, P. (1998) 'Are you sitting on your qualitative data? Qualidata's mission', International Journal of Social Research Methodology, Vol. 1 (1): 85-89.

Corti, L., Foster, J., Thompson, P. (1995) 'Archiving qualitative research data', Social Research Update, Issue 10.

Glaser, B.G. (1992) Basics of Grounded Theory Analysis. Mill Valley, CA: Sociology Press.

Hammersley, M. (1997) 'Qualitative data archiving: some reflections on its prospects and problems', Sociology, vol. 31(1): 131-42.

Hinds, P.S., Vogel, R.J., Clarke-Steffen, L. (1997) 'The possibilities and pitfalls of doing a secondary analysis of a qualitative data set', Qualitative Health Research, vol. 7(3): 408-24.

Kirschbaum, M.S. and Knafl, K.A. (1996) 'Major themes in parent-provider relationships: a comparison of life-threatening and chronic illness experiences', Journal of Family Nursing, vol. 2(2): 195-216.

McLaughlin, E. and Ritchie, J. (1994) 'Legacies of caring: the experiences and circumstances of ex-carers', Health and Social Care in the Community, 2: 241-53.

Popay, J., Rogers, A., Williams, G. (1998) 'Rationale and standards for the systematic review of qualitative literature in health services research', Qualitative Health Research, vol. 8 (3): 329-40.

Procter, M. (1993) 'Analysing Other Researchers' Data' in Gilbert, N. (Ed.) Researching Social Life. London: Sage.

Sandelowski, M. (1997) '"To be of use": enhancing the utility of qualitative research', Nursing Outlook, vol. 45(3): 125-32.

Szabo, V. and Strang, V.R. (1997) 'Secondary analysis of qualitative data', Advances in Nursing Science, vol. 20(2): 66-74.

Thorne, S. (1990) 'Secondary Analysis in Qualitative Research: issues and implications' in Morse, J.M. (Ed.) Critical Issues in Qualitative Research Methods. London: Sage.

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