Primary sources include original research papers authored by the scientists who conducted the study. Also considered primary sources are epidemiologic statistics published by authoritative sources such as the CDC or a hospital or other health system.
Secondary sources are those that report or summarize the work of others. Examples are clinical articles, textbooks, encyclopedias.
Tertiary sources include critical review, meta-analyses, qualitative systematic reviews, and clinical guidelines from authoritative sources.
From TCNJ NURS 604 assignment guidelines
A review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyse data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyse and summarise the results of the included studies.
From Glossary of Cochrane Collaboration and research terms (https://community.cochrane.org/glossary#letter-S)
An experiment in which two or more interventions, possibly including a control intervention or no intervention, are compared by being randomly allocated to participants.
From Glossary of Cochrane Collaboration and research terms (https://community.cochrane.org/glossary#letter-R)
A refereeing process for checking the quality and importance of reports of research. An article submitted for publication in a peer-reviewed journal is reviewed by other experts in the area.
From Glossary of Cochrane Collaboration and research terms (https://community.cochrane.org/glossary#letter-P)