Professors often want you to use scholarly journal articles for your assignments.
Sometimes, they will require you to use scholarly journal articles that contain quantitative research.
Quantitative research looks at factors that can actually be measured in some way, in other words, quantified. It produces numerical results that can be analyzed statistically.
Quantitative research commonly involves experimentation, surveys, or questionnaires in the context of a large, randomly selected group.
The term empirical research is often used as a synonym for quantitative research, but strictly speaking, empirical research is simply any form of research based upon direct observation. It might also be quantitative, but it might not.
PLEASE NOTE: Some professors use these two terms interchangeably. When this occurs, they are usually referring to articles that fit the quantitative description above.
HINT: Don't use the words "quantitative" or "empirical" in your keyword searches. They usually do not appear in article titles, abstracts, or subject words. Instead, check the articles you find to see if some sort of numerical measuring and statistical analysis is present along with the characteristics listed on the right.
Watch for these features when determining if an article has quantitative research. They may appear in the abstract, or you may need to skim the text of the article to find them.
Author credentials (degrees earned, where they work, etc.)