According to the Encyclopedia of Research Methods, "literature reviews are systematic syntheses of previous work around a particular topic."
A literature review finds, summarizes, organizes and presents a body of knowledge on a topic.
When evaluating research studies, include information about the methods used to collect and analyze the data.
According to the International Encyclopedia of the Social Sciences, qualitative methods yield:
According to the International Encyclopedia of the Social Sciences, quantitative research
Original document, source or text without any criticism or interpretation. Includes primary research articles that report the results of original research.
An analysis, interpretation or evaluation of primary source information. Includes opinion, review, discussion or summary.