Evidence-based Methodology

For a clinical reference to truly be called 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, consistently and systematically selected, consistently and systematically evaluated and summarized, consistently and systematically synthesized and interpreted, and continuously adjusted as new evidence becomes available.

Identifying the evidence

To ensure that DynaMed Plus (and DynaMed) provides the best available evidence, an extensive set of current literature is monitored daily. Systematic Literature Surveillance is conducted using many journals, journal review services, systematic review collections, guideline collections and other sources considered relevant to a point-of-care clinical reference. See DynaMed Plus Content Sources . These sources are derived from systematic evaluation of which sources and search strategies provide the greatest yield for identifying the most valid, relevant evidence (meeting criteria for step 2) included in DynaMed Plus.

Selecting the best available evidence

Each article is assessed for clinical relevance, and each relevant article is further assessed for validity relative to existing DynaMed Plus content. The most valid articles are summarized, the summaries are integrated with DynaMed Plus content, and overview statements and outline structure are updated based on the overall evidence synthesis. Article selection is completed by editors with clinical expertise and training in scientific analysis. Relevance is determined primarily by results affecting clinical outcomes and clinical decision-making, and secondarily by consideration of popular or frequent clinical questions. Validity is determined by type of conclusion—download the full version below for more detail.

Critical appraisal

Conclusions may be labeled as level 1 (likely reliable) evidence where conclusions are based on sound research findings meeting a comprehensive set of criteria to support reliability, level 2 (mid-level) evidence for comparative evidence regarding clinical outcomes with some potential shortcomings, or level 3 (lacking direct) evidence where there is no comparative evidence informing effects on clinical outcomes. See Levels of Evidence for details. Full-text evaluation of articles for critical appraisal is required for any article potentially rated as level 1 (likely reliable) evidence, or if detailed explanation is needed for descriptions of important clinical factors. If serious methodological shortcomings are discovered (sufficient to affect clinically relevant results), the shortcomings are described. Critical appraisal is completed by editors trained in critical appraisal.

Objectively reporting the evidence

DynaMed Plus editors check the data against original study reports, and clinical editors review all summaries for validity and relevance at the point-of-care. Level of evidence labeling is done by protocol with explicit reasons stated for downgrading levels of evidence. Shortest unambiguous phrasing is used. Absolute risk data is used and NNT/NNH are presented where available. Clinical editors review all evidence summaries for validity and relevance at the point-of-care.

Synthesizing multiple evidence reports

Evidence-based summarization of articles is necessary but insufficient for a point-of-care reference. Understanding the best current evidence requires synthesizing multiple evidence reports. Preference for inclusion and organization is based on the quality of evidence. When data of lesser quality does not add any substantially new or different information, this data is then deleted. Evidence is also synthesized with guidelines, and areas of inconsistency are presented. Clinical editors review all synthesis results for validity and relevance at the point-of-care.

Basing conclusions on the evidence

In DynaMed Plus, multiple evidence reports of similar quality are organized such that the overall conclusions quickly provide a synthesis of the best available evidence. Overviews, Testing overviews, Treatment overviews, and Overviews & Recommendations (used to synthesize the most important evidence and guidance across topics) are explicitly based upon and linked directly to the supporting evidence synthesis. Editors confirm that overviews are clinically useful and accurately match supporting data.

Updating daily

The final step in 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. As soon as new evidence is evaluated using the 6 steps governing systematic processing, it is added to the appropriate DynaMed Plus topic(s) in context. This process allows immediate and comprehensive access to the best available evidence as it occurs. This process occurs every day in DynaMed Plus.

Download the full version of the DynaMed Plus evidence-based methodology Download the e-book