While writing a systematic literature review (SLR), selecting both criteria is necessary. The setting of inclusion, and exclusion criteria depends on the field of study. Like other secondary sources of data, an SLR addresses specific research questions. This is done in the light of previous studies. And in SLRs, researchers use these criteria for narrowing large data groups. Before conducting a systematic literature review, the researchers define their goals. These goals are major drivers of exclusion and inclusion criteria for a systematic literature review.

Steps for conducting an SLR

Both these criteria stand at the third number. They are among the eight necessary steps for managing a systematic literature review. The necessary steps of the systematic literature review are as follows;

• Step 1: Analysis of existing protocols
• Step 2: Specifying research questions for the SLR
• Step 3: Setting the inclusion, and exclusion criteria
• Step 4: Conducting research
• Step 5: Choosing studies based on the inclusion list
• Step 6: Extracting data from the selected literature
• Step 7: Checking the intensity of brassiness within selected data
• Step 8: Concluding results based on the information gathered so far.

The inclusion and exclusion of data are essential parts of conducting an SLR. Without appropriate selection/rejection criteria, researchers cannot fulfil the needs of SLR.

Exclusive Criteria

Before starting a research, a good sketch of both criteria is important. Both terms, exclusion and inclusion, are somewhat adjacent. The literature rejected by following inclusion criteria will become a part of the exclusion list. Systematic literature reviews often exclude some studies due to certain limitations.

Non updated publishing

In the list of exclusion criteria, the date of publishing matters a lot. Most academic researches need data from the last 5-10 years. The custom range option present at the right side of ‘google scholar home page’ is helpful in this aspect. This is because it helps researchers in excluding outdated data.

Language of the paper

Another exclusion criterion in conducting an SLR is written language of the paper. Most of the time, students in the 3rd world prefer ‘English’ as their research language. For example, you live in England. In this case, you must consider the data for SLR published in British English. You will exclude articles in any other language such as Turkish.

No match with the research’s keywords

The most convenient way of conducting an SLR is through exploration of the world of literature. This is done by using specific keywords. The keyword searching technique helps in finding relevant literature. You can these for your study. The literature that does not contain keywords will automatically enter exclusion list of the SLR.

Too difficult to understand

In general practice, researchers may add any studies to either list. In case the researcher is unable to understand key concepts of a paper, he would reject it. Hence, critical understanding of research also affects the selection, or rejection of studies for SLR.

Doubled credibility of research

As a researcher, the initial estimation of source based credibility is an important, but difficult process. While ensuring your inclusion and exclusion criteria, two things are important. These relate to validity, and reliability of secondary sources.

Research from under developing countries

In most underdeveloped countries, scientists are unaware of the ethical consideration. This is related to the conduction of research. They mostly rearrange data to dodge plagiarism checking tools. They also publish literature with false research. The inclusion of false, or hypothetical data in the SLR also decreases a research’s authenticity. Hence, geographical limitation is an important factor. This is because it affects the inclusion, and exclusion criteria setting protocols.

Inclusion Criteria

The inclusion criteria selection depends on protocol and research questions of a study. In this regard, both terms are the same. Again, the inclusion and exclusion list for systematic dissertation literature review run side by side. It is a binary function. So adding literature in any one of the two lists will subtract that article from the other. The inclusion criteria are topic-specific. But still, a few things that help researchers in finalising inclusion criteria are as follows;

Data from credible websites

In general terms, the inclusion of data in SLR depends on sources of data collection. For example, you want to solve some health care problem. In this case, relevant sources may include the following;

• Google Scholar
• PubMed
• MEDICINE
• NSH official website
• WHO official website
• NCBI
• Scopus

The above mentioned are only a few types of reliable data collection sources. Yet, the selection of sources depends on field of study.

Abstract, or conclusion sections

There is no specific time for adding studies in either inclusion, or exclusion list. It solely depends on the researcher. This decision also depends on the type of information in the abstract. Or what is reflected in the previous studies’ conclusion sections. The abstract is the most readable part of a paper. Thus, reading these sections is the shortest way to decide whether you want to add a study or not.

Keyword’s selection

If you select some keywords for conducting the research, it will lead you to the right path. So we can say that keywords are important to specify both inclusion, and exclusion criteria for SLR.

Recent studies

While conducting SLR, the researchers must include studies not older than the last ten years. So before selecting an article, a review of the date of publication is very important. If the article is updated, then the next step should be ensured. This is about the testing of whether it contains the keywords of our choice or not. In the end, the final decision depends on the abstract’s information.