There are two broad types of evidence: secondary and primary.

We list secondary first because in Evidence-Based Practice it is the higher level of evidence and will probably be what you seek first in answering a clinical or research question.

Secondary evidence (filtered, pre-appraised)

This is evidence assimilated, or put together, from a number of quality primary studies on a topic. It includes systematic reviews, meta-analyses, and evidence summaries.

This is sometimes referred to as filtered or pre-appraised evidence.

You can find it in specialised EBP sources such as The Cochrane Library (notably in the Cochrane Database of Systematic Reviews), and in health and medical databases such MEDLINE, PubMed and CINAHL Plus with Full Text. 

Primary evidence (unfiltered)

This body of evidence consists of original individual studies such as controlled trials, cohort studies, and case studies.

This is sometimes referred to as unfiltered evidence.

You can find primary studies in specialised EBP resources such as The Cochrane Library, notably in the Central Register of Controlled Trials (CENTRAL) and in health and medical databases.

For more information see the Levels of Evidence page in our Evidence-Based Practice Guide.

Evidence Based Databases, such as those mentioned below, enable you to locate secondary pre-appraised research.

Other Databases that have evidence based material:

These resources can be accessed from the Dentistry & Oral Health Journal Databases page.

Journals

The Cochrane Library database investigated in this guide is just one of the evidence based databases you have access to through the CSU Library. For information on other databases you might find helpful please see the Evidence-Based Practice Guide