Informations needs, asking questions, and some basics of research studies

This chapter will provide background information that you need to know in order to understand the details of the evidence-based practice process that follow in the subsequent chapters of this book. In that sense, this chapter is a somewhat diverse but important collection of topics. We start by describing the types of clinical information needs health professionals commonly have and discuss some of the methods that health professionals use to obtain information to answer their needs. As we saw in Chapter 1, converting informational needs into an answerable, well-structured question is the first step in the process of evidence-based practice and, in this chapter, we will explain how to do this. We then explain the importance of matching the type of information you need with the type of study design that is most appropriate to answer your question. As part of this, we will introduce and explain the concept of 'hierarchies of evidence' for each type of question. In the last sections of this chapter, we will explain some concepts that are fundamental to the critical appraisal of research evidence, which is the the third step in the evidence-based practice process. The concepts that we will discuss include internal validity, chance, bias, confounding, statistical significance, clinical significance and power.