Finally, the time will come to combine the presenter's expertise, the audience's needs, and the available scientific evidence into a useful presentation. In some instances, evidence-based clinical guidelines will already have been developed on topics related to your particular presentation. There are at least two important factors to keep in mind when considering whether and to what extent to include the guidance contained in such documents.
Many guidelines are produced via an expert consensus process or other non-systematic approaches. While expert consensus can certainly be a valuable source of information, the conclusions are particularly vulnerable to the biases held by the "experts," and history is full of examples of such conclusions being simply wrong.
If a guideline is truly evidence-based, the methodology by which evidence was identified and evaluated should be transparent. Unfortunately, transparency in itself is not a guarantee of quality. It can be a challenge to determine what is and is not a high quality evidence-based practice guideline. Systems for evaluating practice guidelines have been developed and can be useful tools to help determine whether a guideline should be accepted. The most prominent of these tools is the Appraisal of Guidelines Research and Evaluation (AGREE) framework. AGREE was developed by the European Union and has subsequently been endorsed by the U.S. Agency for Health Research and Quality (AHRQ).
Although many guidelines are produced by academic institutions and interdisciplinary collaborations, others are produced by advocacy groups or payors. It is important to consider who produced the guidelines and to what extent they would likely be affected by positive or negative recommendations. However, guidelines emanating from a "trusted" source are no more guaranteed to be of high quality than are guidelines coming from a less objective source guaranteed to be flawed. Application of the AGREE or other objective criteria should be the final determinant of the guideline's quality.