Complementary research paradigms.

methodologies operate broadly within qualitative and/or quantitative paradigms. The simplest distinction between these two is that quantitative research methods involve enumeration, whereas qualitative research methods employ qualitative (non-numerical) judgements in exploration of the phenomena being studied. Behind this simple distinction lie deep philosophical differences. Quantitative research paradigms are rooted in the positivist belief that there are simple universal truths which can be discovered with objective methods. Criteria such as validity, reliability and generalisability are used to assess the quality of the research. To a large extent quantitative research predominates in the physical world. In contrast, there are a range of qualitative research paradigms (e.g. interpretive, critical, feminist) that are grounded in different philosophical traditions (e.g. idealism, historical realism). In general, these traditions have identified a need to move beyond an objective view of the world so that the complex human world can be examined in context from the subjective perspectives and complex truths of different individuals. These qualitative approaches employ terms such as credibility, trustworthiness and transferability as quality criteria. Despite their philosophical and methodological differences, research approaches across the paradigms can provide complementary ways of learning, particularly in areas such as health care which are concerned with both the physical and social worlds. In past decades much has been made of 'paradigm wars' which were divisive and unhelpful. In our view both qualitative and quantitative paradigms can generate valuable knowledge and there are many cases where the different approaches can be conducted in conjunction and harmony. In the following paragraphs we briefly outline what we see as being the primary roles and limitations of qualitative and quantitative research methodologies. The role of quantitative research methods Sometimes quantitative methods are necessary because the research question demands quantitative answers. Questions such as 'In young adults with primary shoulder dislocation, what is the probability of re-dislocating within one year?' or 'By how much can bone growth stimulators reduce healing time of tibial fractures?' can only be answered satisfactorily with quantitative methods. More often questions are amenable to investigation with either qualitative or quantitative methods, but quantitative methods may be selected because they offer particular advantages. One strength (but also a weakness) of quantitative methods is that they provide a convenient way of describing complex data sets. For example, several hundred patients' responses to a series of questions about depression might be reduced to a mean depression score. This single number provides a …