Most of the article databases available through B.C. Libraries provide a way to limit search results to peer-reviewed publications*. Look for a checkbox or drop-down menu item that says one of the following:
*Caution! Just because you limit your search to results from peer-reviewed journals does not mean that all articles in the search will have been peer-reviewed. Academic journals include many types of writing (e.g., editorials, reviews, letters, etc.) that are not peer-reviewed, and will likely appear in search results. When in doubt, check with your instructor.
If the database you are using does not have a peer-review/academic checkbox, you can use Ulrich's Periodicals Directory to find out whether the journal is peer-reviewed. Just type the periodical title into the search box, and then find the entry for that title in the search results. If you see the icon of the referee jersey to the left of the title ( 
), the journal publishes peer-reviewed articles.
Caution! Just because a journal publishes peer-reviewed articles doesn't mean that everything in the journal is peer-reviewed. Editorials, letters, book reviews, and some other types of writing are rarely peer-reviewed. When in doubt, check with your instructor.
A journal’s Impact Factor (IF)--a measure of how frequently articles in a journal are cited by other writers*--is often used to judge the quality of a journal. Use Journal Citation Reports (JCR) to assess the IF of over 12,000 Institute of Scientific Information (ISI) journals. The Web of Science also uses the ISI database of citations, and allows you both to compare citations of articles and click hyperlinked citing articles, or even find similar articles based on citation patterns.
Other measures of impact:
Google Scholar Metrics (h-index, h-median)
Eigenfactor® Score and Article Influence® Score
Cautions: One of the major concerns associated with these measures is that only a small number of journals have them, i.e. only those journals indexed by JCR (over 8,000 journals in Science and 2,700 in the Social Sciences). Also, certain fields and journal types will necessarily have smaller IF's, simply because those fields are either narrow or don't cite as heavily. A high-profile periodical like Nature has a very high IF partly because it has broad distribution, covers many areas in science, and is in a field that values citation highly. Some humanities and social science journals are very important but have narrower distribution, cover narrow areas, and participate in fields that don't cite as heavily. When comparing journal IF's, compare only within fields, not across fields.
Assessing Article and Author Influence
*Formula: ISI’s IF is calculated by dividing the number of current year citations by the total number of articles published in the two previous years. An IF of 2.0 signifies that, on average, the articles published up to two years ago have been cited twice.
