Words to look for as clues include: analysis, study, investigation, examination, experiment, numbers of people or objects analyzed, control group, or survey.
* Literature reviews and meta-analyses also describe the authors' research method/methodology, focusing on their database search strategy and development of criteria for including or excluding individual study results. These articles are still secondary sources because they synthesize the findings of multiple research studies; the authors are not the primary researchers.
Research study types are not always obvious. Researchers may use elements of more than one design to achieve their purpose. Read carefully and use your best judgement to identify the overall category or type of a particular study's methodology.