What is Qualitative Research? What is its role in Evidence Review?

Qualitative research encompasses a range of specific methods generating different kinds of data and findings. These include: in-depth qualitative interviews producing narrative data, participant and non-participant observation, focus groups and ethnographic fieldwork. Inevitably, given this range of data types, there are also diverse approaches to analysis. These include the use of statistical packages such as Nudist and Ethnograph, as well as grounded theory approaches. The identification and refinement of thematic categories is a major aspect of qualitative analysis.

Qualitative research can help us to understand the way in which an intervention is experienced by all of those involved in developing, delivering and receiving interventions, what aspects of the intervention they value, or not, and why. These types of studies can provide insight into the factors, including aspects of professional, managerial and/or consumer behaviour and external factors such as other policy developments, that facilitate or hinder successful implementation of a program or service and how it might need to be adapted for large scale roll out. They may also generate qualitative data on the outcomes of interventions. The findings from qualitative research studies can therefore help to answer questions about the impact, appropriateness and acceptability of interventions and thus enhance the scope, relevance and utility of effectiveness reviews

The relevance of qualitative research to the assessment of health interventions has only recently being given recognition although it has long been recognised in other fields, notably education, where RCTs often include qualitative elements. Increasingly, however, qualitative components are being built into RCTs of health interventions. Additionally, it is important to consider the potential contribution of qualitative research conducted outside of RCTs.

The findings of high quality randomised controlled trials are central to the endeavours of both Collaborations. However, it is increasingly recognised that findings from qualitative studies aiming to explore the experience of all those involved in providing and receiving interventions and studies using multiple methods to evaluate the factors that shape the process of implementing interventions have an important role to ensuring the systematic reviews are of maximum value to policy and practice decision-making.

In theory, findings from qualitative research and studies of the implementation of interventions can make a number of specific contributions to systematic reviews of the effectiveness of particular interventions. These include:

• Influencing the criteria by which effectiveness is to be judged and hence the process and outcome data to be extracted from trials;
• Providing a research-based context for interpreting and explaining trial results including insights into how change was achieved, whether it could be achieved more cost-effectively and the factors that constrained/facilitated change;
• Contributing to understanding of heterogeneity in outcomes;
• Providing evidence on the subjective experience of all those involved in developing, delivering and receiving an intervention;
• Revealing the extent to which the criteria adopted to judge effectiveness are actually adopted in policies and practice; and
• Contributing to the methodological development of systematic reviews by expanding the existing concern with publication bias to include other forms of bias in the production of systematic reviews.

Members of the Methods Groups are exploring these potential uses in the context of existing Cochrane and Campbell systematic reviews as well as systematic reviews undertaken by others.. This work is also intended to address methodological issues. The inclusion of qualitative studies into systematic reviews of evidence raises a number of important methodological issues. At a general level, methodological work is required to determine whether it is 'reasonable' to apply findings from independent studies to the results of a systematic review of RCTs or whether only qualitative research embedded within relevant RCTs should be included. Other methodological issues arising from the inclusion of qualitative findings into systematic reviews include the need to develop methods for identifying, recording, appraising and extracting data from qualitative studies.

1. Search strategies:

   In terms of identifying relevant studies, there are implications for the development of registers of studies and for search strategies. Most registers of RCTs, for example, do not routinely record the availability of data from qualitative studies collected during RCTs and/or as part of linked studies. Conventional search techniques may not pick up relevant material. Search strings to identify qualitative studies using a range of different qualitative methods need to be further developed.

2. Critical appraisal:

   Tools are being developed which seek to deal with the interpretative nature of the qualitative research process but there is a need to review, test and disseminate different models and to consider the appropriateness of different approaches for use with studies using different qualitative methods.

3. Evidence synthesis:

   Finally, there is a need for methodological work on the processes by which findings from studies using different qualitative methods and generating a range of types of data can be synthesised and/or summarised and combined with the findings on effect size without compromising the need to minimise bias. Here there is a more general issue to be addressed. Given the importance of 'context' to qualitative research there is a need for methodological research to clarify the basis on which findings from such research can be generalised across studies undertaken in different socio-cultural conditions.