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Chapter 5: Appraising the evidence
  1. Phil Wiffen1,
  2. Tommy Eriksson2,
  3. Hao Lu3
  1. 1Pain Research Unit, Churchill Hospital, Oxford, UK
  2. 2Department of Clinical Pharmacology, Laboratory Medicine, Lund University, Lund, Sweden
  3. 3Department of Pharmacy, Beijing United Family Hospital, Beijing, China
  1. Correspondence to Professor Phil Wiffen, Pain Research Unit, Churchill Hospital, Oxford OX3 7LE, UK; phil.wiffen{at}

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Evidence-based Pharmacy was first published as a book by Phil Wiffen in 2001. The first chapter was published in Eur J Hosp Pharm 2013;20:308–12.

In the first edition of Evidence-based Pharmacy, Chapter 5 covered issues on accessing evidence. Since that time, accessing information via search engines on the internet has become commonplace such that it no longer warrants a separate chapter.

This chapter now deals with tools that can be used for assessing the quality of evidence using appraisal tools. While we may think that quality is assured by processes such as peer review or even the reputation of a particular journal, in reality that is often not the case. It is important that we make our own judgement before using an article in our practice. In this chapter, tools to help with that appraisal process for a range of study designs are presented. At the end of this article, we present some thoughts on appraising patient-oriented outcomes.

We present an algorithm to help identify study designs (figure 1). This is based on an idea from SIGN.1

Figure 1

Algorithm of study designs.

Observational and experimental research

There are two ways to test a hypothesis, either by observation or by experiment.

Observational research

In observational research, the researcher observes a population or group of patients or manipulates data about these patients. Such data may come from interviews or from existing data sets such as prescription analysis data or registries for particular diseases such as cancer or infectious disease. Surveys and case control studies are examples of observational research. A great deal of the research around pharmacy services is, of necessity, observational in style. Observational research is likely to be more biased but is still necessary and sometimes the only means to answer certain questions.

Experimental research

In experimental research, an intervention is performed as part of a planned …

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  • Competing interests None.

  • Provenance and peer review Commissioned; internally peer reviewed.