What is peer-review: ~ It functions as a filter for content ~ Content has been critically evaluated by other experts in the field
~ Contain citations (footnotes and/or bibliography) documenting sources
~ Reviewers can have their own biases
~ The length of time it takes for an article to go through the process means the data can be years old by the time it is published
~ May not identify errors in research
Journal Impact Factors
There are a number of ways the relative importance of journals are ranked. They are also calculated differently.
Citation and article counts are a couple of indicators of how frequently current researchers are using individual journals.
"You should not depend solely on citation data in your journal evaluations. Citation data are not meant to replace informed peer review. Careful attention should be paid to the many conditions that can influence citation rates such as language, journal history and format, publication schedule, and subject specialty." JCR