Developing a research study

Identifying the research problem and evidence base

Sometimes, a research project might emerge organically from the development and evaluation of an intervention. For example, a choir set up to support people with lung disease might have such good evaluation results that it is decided that a formal research project to explore these effects in more detail should follow. In this case, the previous consultation work to design the intervention might have involved a thorough search of previous research literature prior to the intervention being run. However, a research project could equally emerge from a research question (such as ‘does singing improve lung function in lung disease?’) with the plan that an intervention is developed to test this. In this case, a literature search may be undertaken after the initial research idea. Either way, understanding the existing evidence base is a crucial first step in a research project.

At the simplest level, evidence reviews could involve eliciting expert advice from established researchers about what research has been carried out (see Table 10.1, level 1). Such advice is often very helpful in narrowing down the potential area of interest. However, it is not a substitute for exploring the evidence base in more detail. This further exploration can be important both to identify more precisely what questions have been asked and what evidence has been found, and also to find out about interventions that have been explored and how they were designed. Of course, it is possible that the topic may not have been researched at all. In this case, it can be helpful to explore related literature (such as breathing exercises for lung disease) (level 2). With level 3, there is more of an engagement with the literature: previous studies can be reviewed

Table 10.1 The spectrum of options for identifying the evidence base

and ‘gaps’ for further work identified, meaning that the new research project builds on past evidence and takes a logical next step in exploring the topic. In level 4, a systematic review is undertaken. This involves finding every single previous study in the field. It is normally carried out with searches using relevant keywords of online research databases. This ensures that the new research project does not inadvertently duplicate previous work. However, it requires a greater time commitment so is normally reserved for larger research studies. For smaller studies, is it sometimes possible to find systematic reviews that have been published, which could have undertaken much of the work already (although such reviews do date very quickly, so often a manual search for more recent articles is necessary too).

Finally, level 5 involves a systematic review with meta-analysis. A metaanalysis statistically combines the findings from independent studies and looks at the overall aggregated results. So, for example, if a systematic review showed 12 studies about singing and lung function, if the studies had been carried out in similar ways with the similar outcome measures, it might be possible to look statistically at whether all 12 studies together showed evidence that singing helped lung function, providing an overall greater sample size and richer data. However, meta-analyses are often not possible if there are relatively few studies or they have not used comparable interventions.

The PRISMA checklist is a 27-item checklist for undertaking systematic reviews and meta analyses, showing what information should be collated and reported. It is available along with further resources at www.prisma-statement.org.