A practitioner's guide to developing critical appraisal skills: the fundamentals of research

This is the first of a series of articles summarizing the basic principles and methods of research with an emphasis on clinical investigation. In today's environment of evidence-based practice, the prevention of, diagnosis of, prognosis for and treatment of oral diseases must be based on a critical evaluation of available research. The purpose of this series is to help practitioners understand research and develop skills in interpreting research published in the medical and dental literature.

Research involves systematic investigation and can be categorized in different ways. Primary research may take several forms and includes basic and applied research. Basic research seeks fundamental knowledge without having a specific application; applied research is conducted for the purpose of a specific application and often is predicated on basic research findings. Applied research may take several forms and includes clinical research, which seeks to inform patients, clinicians, public health workers and policymakers about methods of preventing and treating diseases. Secondary research involves the use of existing data and results of published scientific studies. Systematic literature reviews are a form of secondary research that attempt to remove bias often associated with narrative reviews.