"Evidence-based" is a descriptor that is often used to describe health care-related reference resources.

For a clinical reference resource to truly be evidence-based, conclusions must be based on the best available evidence. Conclusions can be based on the best available evidence only if the evidence is consistently and systematically identified, evaluated and selected.

In addition to being reviewed and updated on an annual basis by the Medical Review Board, PERC content is periodically updated using EBSCO DynaMed Literature Surveillance findings. The Dynamed Editorial Team performs daily literature surveillance of 500 journals and generates reports on the most significant research. The PERC Editorial Team reviews the reports each week and updates all applicable content affected by these reports. This ensures that content in PERC captures both significant and current research being conducted in medicine today.

The EBSCO DynaMed editorial process adheres to the following strict 7-Step evidence-based methodology and protocol:

1. Systematically identify the evidence
2. Systematically select the best available evidence from that identified
3. Systematically evaluate the selected evidence (critical appraisal)
4. Objectively reflect the relevant findings and quality of the evidence
5. Synthesize multiple evidence reports
6. Derive conclusions and recommendations from the evidence synthesis; obtain peer review
7. Change the conclusions when new evidence alters the best available evidence

Step 1: Identify the Evidence

Perform systematic searching
When adding a new topic or critically revising an existing topic, appropriate databases (DynaMed, MEDLINE, CINAHL and others) are searched to identify the best available evidence. In addition, numerous sources are searched for evidence-based reviews (such as Cochrane Database of Systematic Reviews), for guidelines (such as National Guideline Clearinghouse), and more.

Step 2: Select the Best Available Evidence
Each article is assessed for clinical relevance and each relevant article is further assessed for validity relative to existing PERC content.

Determine Relevance
Determining clinical relevance is the first consideration in systematically selecting the best available evidence from the literature retrieved. The relevance of information is different for every user. Patient Education Reference Center content is developed for a consumer/patient audience. When adding information the following is considered:

1. This information has a direct bearing on patient-oriented outcomes.
2. This information is useful for patient education purposes.
3. In situations where the evidence does not clearly support or refute a clinical fact, opposing views are presented.
4. Some medical information is not clinically relevant, but is widely publicized. Summarization of this type of information is relevant to the clinician if it is likely that they will be asked about it during clinical encounters.

Determine Validity
Clinically relevant articles must be assessed to determine the scientific validity of conclusions and facts presented before consideration for use.

Step 3: Evaluate the Evidence (Critical Appraisal)
Examine the article to evaluate the article’s methodologic quality and results and determine its level of evidence.

Step 4: Objectively Reflect the Relevant Findings and Quality of the Evidence

When reporting the evidence, the following is considered:

1. What are the most relevant outcomes to report in the topic?
2. Were all relevant outcomes reported in the original article?
3. For relevant outcomes, what is the magnitude of effect?
4. Were the findings clinically significant?
5. In the case of no statistically significant differences, were the findings robust enough to rule out clinically significant difference?
6. Are there any methodologic limitations sufficient to alter reliability of clinical conclusions?

Step 5: Synthesize Multiple Evidence Reports
Evaluate the findings, both positive and negative, from the relevant articles and organize in a systematic fashion.

Step 6: Derive Conclusions and Recommendations from the Evidence Synthesis; Obtain Peer Review
Based on the synthesis of relevant evidence, conclusions about current knowledge are drawn and recommendations for clinical practice are made.

Step 7: Change Conclusions When New Evidence Alters the Best Available Evidence
The final step in our evidence-based methodology is changing conclusions when new evidence alters the best available evidence. This step is crucial because new evidence is published every day. Having new evidence summaries handled separately from reviewed content in a manner requiring the nurse or clinician to search in two locations to synthesize the entire story would make finding the best available evidence more difficult. As soon as new evidence is evaluated, it is added to the appropriate topic(s) in context.