Qualitative and quantitative methods in health research

INTRODUCTION: Research in the area of health has been traditionally dominated by quantitative research. However, the complexity of ill-health, which is socially constructed by individuals, health personnel and health authorities have motivated the search for other forms to approach knowledge. AIM: To discuss the complementarities of qualitative and quantitative research methods in the generation of knowledge. CONTENTS: The purpose of quantitative research is to measure the magnitude of an event, to make predictions, develop causal explanations. To achieve this it uses a pre-established design based on hypothesis and theories, conducts extensive data collection to a statistical sample and develops statistical data analysis. Quantitative research objectives can be to establish the incidence or prevalence of a health problem; the health personnel degree of adherence to a new intervention; or, the users’ level of satisfaction with a service. Qualitative research aims at understanding what exists from social actors’ perspectives. Its design is open, flexible and circular, data collection is intensive and based on a purposive sample and results will be achieved through inductive analysis. Qualitative research allows to explore aspects thought as known, understands differences in personnel opinions and practice in front of new interventions or users’ opinion on services utilization. CONCLUSION: Quantitative and qualitative methods are different research approaches, that not only provide complementary knowledge that contributes to gaining better understanding of a problem or situation, but that can be used in a combined way, to approach a new research area, to develop instruments and to interpret results.