How To Do Secondary Research or a Literature Review

Citing your sources is the most important step towards honesty and transparency. The sources you use and cite are supposed to be those that helped you to refine your topic and to understand both the background of your current research and its implications. They should be clearly identified so other researchers can understand your thought process and to acknowledge the work done by those prior researchers. For more information on citing sources, see our guide.

• Read what you cite. To properly incorporate your sources you need to have read and understood them. Resist the temptation to pad your references by simply copying citations from other papers. At best, you will end up with possibly irrelevant citations—at worst, you could end up misrepresenting another researcher’s work.
• Cite what you read. All of the papers you read as part of your secondary research that helped you come to grips with your topic were important and influenced your thinking. They should all be cited. Resist the temptation to cite only the key articles related to your topic.

While truly exhaustive searches are probably impossible, that doesn’t mean you should just stop searching after finding 5 or 10 or 20 papers. Keep going until you think you’ve found “everything.” Admittedly, this takes more time, but you’ll avoid the embarrassment of missing a key paper or worse, the waste of time and money in replicating research already done and reported in a paper you missed.

Use multiple databases and Google Scholar. No one search tool covers all published research, not even Google Scholar. Using multiple tools increases your chances of finding more relevant papers.

Augment your search with artificial intelligence. There are AI tools available to help researchers find more papers related to their research.Some example are:

For more information on  the use of artificial intelligence, see our guide:

Sometimes your secondary research will uncover papers that challenge your theories or your entire line of research. This does not necessarily mean that your line of research is wrong or misguided—just that others believe it to be so or that their experiments did not support your theories. In this case honesty & transparency are vitally important. Explain the counter arguments against your ideas—don’t just sweep them under the table—and then explain why you believe your research refutes these counterclaims.

All research is the product of its time and place. There are many examples of past research that does not meet current standards of research ethics. These could include the use of human subjects without their permission, unregulated animal experimentation, research designed to reach a specific conclusion, etc. If you find relevant papers that exhibit bias or unethical practices during your secondary research, you should acknowledge them in your literature review and explain why you are using or rejecting them. When using unethical research, you should also explain how the information was obtained and acknowledge any practices that are now considered unethical

Retracted papers present an unique challenge when citing sources. Papers are retracted for a variety of reasons, but they all involve either errors or research misconduct by the researchers.

As a general rule of thumb, retracted papers should not be used. However, there are cases where the use of a retracted paper is warranted or even required. Some specific use cases are listed below.

• Normal source of information. An error in one part of the methodology or analysis does not necessarily invalidate all the other parts of the research. Errors can indicate a lack of care or inattention to detail on the part of the researchers, though. Review the other parts of the paper carefully to see if they are free of error. If so, they can be used.
• Counter examples. Papers retracted for errors can serve as examples of how not to do a particular research activity or experiment.
• Correcting the scientific or research record. If your research is intended to correct the errors introduced in the original paper, then you will definitely need to use and cite the original retracted paper.
• Research about research misconduct. If your research is about research misconduct, you will want to use published example of bad research. In this case you will want to specifically look for papers retracted due to forms of misconduct or research fraud.

In all cases, retracted papers should be clearly labeled as "retracted" in your citations and reference lists.