Category: Literature Review

A systematic literature review is a valuable tool that researchers can utilize to gather and analyze existing knowledge and evidence related to a specific research topic. It involves a comprehensive and rigorous approach to reviewing published studies, academic papers, and other relevant sources of information. By conducting a systematic literature review, researchers can gain a deeper understanding of the existing body of knowledge, identify research gaps, and inform their own research design and methodology. This blog explores the various ways in which researchers can take advantage of a systematic literature review when conducting their research, highlighting its benefits and significance in the research process.
Before diving into the topic, we need to know the examples of systematic literature review topics to fully know how we can take advantage of it. So, let’s dive into it.

Examples of systematic literature review

Here are a few examples of systematic literature review topics across different disciplines;

1. The impact of mindfulness-based interventions on stress reduction: A systematic literature review and meta-analysis.
2. Effectiveness of cognitive-behavioral therapy in treating depression: A systematic review and meta-analysis of randomized controlled trials.
3. The role of nutrition in preventing cardiovascular diseases: A systematic literature review of observational studies and clinical trials.
4. The effects of exercise on cognitive function in older adults: A systematic review and meta-analysis of randomized controlled trials.
5. The effectiveness of school-based bullying prevention programs: A systematic review of intervention studies.
6. The impact of social media on body image dissatisfaction and disordered eating behaviors: A systematic literature review.
7. The role of artificial intelligence in healthcare diagnosis and treatment: A systematic review of current applications and challenges.
8. The effectiveness of virtual reality-based interventions in pain management: A systematic literature review and meta-analysis.
9. The impact of parental involvement on academic achievement: A systematic review of longitudinal studies.
10. The effectiveness of mindfulness-based stress reduction programs in workplace settings: A systematic review of controlled trials.                                                                                                                                                                                    These examples highlight how systematic literature reviews can be conducted across various research domains, including psychology, healthcare, education, technology, and social sciences.
    To know the ways in which a researcher can take advantage of a systematic literature review, we need to go to the root of it by covering some in-depth questions on it.

So the first question is:

 How does the integration of a systematic literature review into the research process enhance the identification and selection of relevant research gaps and research questions?

The integration of a systematic literature review into the research process can significantly enhance the identification and selection of relevant research gaps and research questions in several ways:

A comprehensive review of existing knowledge:  A systematic literature review involves a rigorous and systematic search and analysis of existing research studies within a specific field or topic. By conducting such a review, researchers gain a comprehensive understanding of the current state of knowledge, identifying what has already been explored and established. This enables them to identify gaps in the existing literature and areas where further research is needed.

Identification of research trends and emerging areas:  A systematic literature review allows researchers to identify research trends, emerging concepts, and innovative approaches within their field. By analyzing a wide range of studies, researchers can observe patterns, recurring themes, or novel ideas that can inform the development of relevant research questions. This process helps them identify gaps in knowledge that need to be addressed or areas where new research directions can be pursued.

 

The second question is

 What specific methodological frameworks or tools can researchers employ to effectively conduct a systematic literature review and extract valuable insights for their research  ?

Researchers can employ several methodological frameworks and tools to effectively conduct a systematic literature review and extract valuable insights for their research. Here are some specific frameworks and tools commonly used:

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses): PRISMA is a widely recognized framework for conducting systematic literature reviews. It provides a structured approach for transparently reporting the review process, including study selection, data extraction, and synthesis. Adhering to the PRISMA guidelines ensures the rigor and transparency of the review.

PICOS (Population, Intervention, Comparison, Outcome, Study Design): PICOS is a framework used to define the key components of a research question for a systematic literature review. It helps researchers specify the relevant population, intervention or exposure, comparison group, outcome measures, and study design characteristics to guide the search and selection of studies.

Number three in this list is,

How can researchers leverage the findings and conclusions from a systematic literature review to inform the development of a comprehensive theoretical framework or conceptual model for their research study ?

Researchers can leverage the findings and conclusions from a systematic literature review to inform the development of a comprehensive theoretical framework or conceptual model for their research study in the following ways:
Identify gaps and limitations: Through a systematic literature review, researchers gain insights into existing theories, models, and frameworks in their field. They can identify gaps, limitations, or inconsistencies in the current body of knowledge. This knowledge allows researchers to position their own study within the context of existing theories and identify areas where their research can contribute to filling these gaps.

Synthesize key concepts and variables: A systematic literature review helps researchers identify the key concepts and variables that are commonly used or emphasized in previous studies. By analyzing the findings from multiple studies, researchers can extract and synthesize these concepts to form a foundation for their own theoretical framework or conceptual model. This synthesis provides a solid basis for developing hypotheses and research questions.

The fourth question is

What strategies can researchers employ to overcome potential biases or limitations associated with the inclusion and exclusion criteria used during the systematic literature review process ?

Researchers can employ several strategies to overcome potential biases or limitations associated with the inclusion and exclusion criteria used during the systematic literature review process. Here are some key strategies:
Clearly define inclusion and exclusion criteria: It is crucial to establish clear and explicit criteria for including or excluding studies from the review. These criteria should be well-documented and based on the research objectives and research questions. Clearly defining the criteria helps minimize subjectivity and potential bias in the selection process.

Use multiple reviewers and inter-rater reliability checks: Involving multiple reviewers in the study selection process can help mitigate individual biases. Each reviewer independently evaluates the relevance of studies against the inclusion and exclusion criteria. To ensure consistency and minimize discrepancies, reviewers can conduct inter-rater reliability checks, where a subset of studies is assessed by multiple reviewers, and agreement rates are calculated. Discrepancies can be resolved through discussion and consensus.

The last question is

How does the utilization of advanced data mining and text analysis techniques within a systematic literature review enhance the identification of emerging research trends, theoretical frameworks, or practical applications that can shape the direction of future research?

The utilization of advanced data mining and text analysis techniques within a systematic literature review can significantly enhance the identification of emerging research trends, theoretical frameworks, and practical applications, ultimately shaping the direction of future research. Here’s how:

Efficient identification and extraction of relevant information:  Advanced data mining and text analysis techniques can automate the process of identifying and extracting relevant information from a large volume of scholarly articles. These techniques can efficiently analyze titles, abstracts, keywords, and full-text documents to identify key concepts, relationships, and patterns that may not be immediately apparent through manual review. This enables researchers to quickly and comprehensively assess the landscape of existing literature.

Identification of emerging research trends:  By applying data mining and text analysis techniques, researchers can detect emerging research trends that may not be easily identifiable through traditional methods. These techniques can identify keywords, topic clusters, co-occurrence patterns, or citation networks that highlight areas of active research or emerging topics within a field. Identifying these trends allows researchers to focus on novel and timely areas for further investigation.

In conclusion, researchers can take full advantage of a systematic literature review by using it as a foundation for their own research, enhancing their critical thinking skills, informing evidence-based decision-making, and fostering collaboration and knowledge exchange. By harnessing the power of existing knowledge, researchers can make meaningful contributions to their respective fields and drive positive change.

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PRISMA Stands for Preferred Reporting Items for Systematic Reviews and Meta-Analysis. The main aim of PRISMA is to help authors improve the reporting of systematic reviews and meta-analyses. It is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. Systematic Reviews and Meta-Analyses are important tools for summarizing evidence accurately and reliably. They have multiple benefits. They help professionals stay up to date, give substantial proof to policymakers to assess the risks, provide a logical ground for guideline creators, and help editors to judge the merits of publishing reports of fresh studies and many more.
Evolution of PRISMA
There is a lot of evidence that systematic reviews could not report key information. This actually diminished the usefulness of systematic reviews. The relevance and importance of systematic reviews are maintained when they are reported fully and also transparently so that readers can assess the strengths and weaknesses of the investigation undertaken. On this pretext, initially QUOROM statement was developed. QUOROM stands for Quality of reporting of Meta-Analysis. It was developed in 1996 and published in 1999 and was conceived as a reporting guide for authors who are reporting a Meta-analysis of randomized trials. Since, there has been a lot of development and expansion in the reporting of systematic reviews but still with all the shortcomings in QUOROM, it was far from ideal and this prompted the need for update. PRISMA came into light with a broader application than the original QUOROM statement and addressed conceptual and methodological issues in greater depth; PRISMA being a development of QUOROM.
Development of PRISMA
The PRISMA statement was developed by a group of 29 review authors, methodologists, clinicians, medical editors and consumers. In the year 2005, over three days long meeting followed by long correspondence meetings a 27 items checklist and a four phase flow chart diagram was developed. All the items found to be necessary in the transparent reporting of systematic review were included in the checklist that was created. The flowchart which was initially proposed for QUOROM was updated, modified to reflect the identified records. Further, after many reviews the flow chart was approved for final inclusion in PRISMA

The 4 stages of a PRISMA flow diagram
The work described in the flow diagram is split into 4 stages:
1.Identifying the articles for review
2.Screening the articles for review
3.Deciding on the studies’ eligibility
4.Finalizing the list of studies to include in the systematic review

1) Identification of the Articles for Review:
In the preliminary stage, you need to take up a search that you have designed through the abstract and citation database that has been selected by you. These could be Scopus, PubMed or any other reliable database. Make a note of the number of records that have been returned by your search. You can also list down the searches you made from different sources such as Google Scholar or even the reference list you can retrieve from other related and relevant articles.
A few important things to take care of at this stage is that one cannot deploy the same search techniques for all databases. Each database has its own unique and specific guidelines that you must adhere to when trying to search relevant articles for review. There are techniques on how to combine keywords or search for keywords of interest that are different for databases. PubMed, for instance, follows a very literal pattern in its search function. If you search the word “medicine” in its titles, you won’t get the list if those titles that include the plural form “Medicines” also. Once you have run searches across all relevant databases you need to combine all shortlisted articles or records under a single citation management program. Google Sheets or Excel can also do a good job of it as conventional tools, but now more sophisticated options are available, such as:
DistillerSR
EndNote
Mendeley
Sciwheel
Despite all care taken, there is a possibility of duplication of records, and you must ensure to remove all duplicate records. Microsoft Excel gives a very handy option in the data tab, which is “Remove Duplicates”. You will just have to specify the column heading as the identified one which you want to select for sorting duplicates.
A very significant suggestion here is to sort the identifiers by DOI. This is because DOI is completely unique in nature. It is a possibility that two articles can have the same titles and in case you delete by sorting on duplication of titles, you may lose an important source for review but by using DOI for sorting this problem can be eliminated. At this stage, you must note that, in the end, how many unique records you are left with.

2) Screening the articles for Review:
At this stage, the researchers go through all the titles and abstracts. By reading each of the articles they can determine whether they contain material which is relevant or helpful to the systematic review. If you decide to exclude articles, you must note down the reason for exclusion and categorize articles based on the reason for which you have decided to not include them in the systematic review. This is a simple “yes/no” choice.
Some of the reasons can be

The article does not have any original data
Absence of control group
The article has no relevance with your research question
There is a mismatch of the population characteristics
 The article is opinionated in nature
Make a note of the number of articles that you excluded and the number of articles under each category of exclusion.
When there is more than one investigator who are working on doing the systematic review, they may decide to not split the articles or divide the workload. If two investigators are there, then both screen every article and abstract, and then they compare their individual decisions. In a situation where there is a difference of opinion about the inclusion or exclusion of a particular article, they both go through the text together and arrive at a mutual decision. In case of confusion, they may ask the principal investigator or project manager o take a call for a specific article.
Do not miss the references of those articles you decide to exclude from your systematic review. They may contain some useful research studies that you can include in your additional records.
3) Deciding on the studies’ eligibility:
Till the second state of screening, the decision about the inclusion or exclusion of an article is taken based on the title and abstract. After having done that, at this stage those articles that get shortlisted are read in full length. The purpose of doing this is to identify whether these articles would help you to answer your research question. In case of two investigators, both perform the full text eligibility screening test and decide to whether to retain or exclude an article. Like the earlier stage, here you must build categories under which you must list down the articles. This clearly specifies the reasons for including or excluding that article after full text analysis. Again, in case of disagreements at this stage, a third person intervention can help in making the right decision about keeping or doing away with a specific article.
4) Finalizing the list of studies to include in the systematic review:
By this stage, you would know clearly about the studies that will be included in your systematic review after eliminating those that are irrelevant to your research question. Make note of this number in your flow diagram. The purpose of this last stage of the diagram is to determine how many of those studies can be included in the quantitative synthesis which in other words is also labelled as meta-analysis. It is possible from all the studies you have shortlisted for your systematic review, not all are eligible for meta-analysis. Meta-analysis is statistical in nature and pools up the data from multiple studies to test the hypotheses. It is quite likely that not all shortlisted studies will have the data that is important for quantitative synthesis. The studies that qualify for meta-analysis must be noted down at the bottom of the flow diagram.
The Assessment of PRISMA
The quality of reporting of the systematic reviews is still not optimal. Survey and analysis has revealed the existence of possible publication bias and its impact on the systematic review. The results are not less than overwhelming. Systematic review does address the issue of publication bias to a large extent but there is no certainty that the investigator or reviewer has done his job of assessment and interpretation fairly. If the researcher brings up an issue of publication bias while performing a systematic review, it is an indication of job done thoroughly. Sometimes investigators show absence in reporting such assessment which does not really mean the absence of it in the process. It can also be attributed to the negligence of the researcher.
Over the years, since the inception of systematic reviews, its application has broadened and it can now be applied to a large array of questions. For instance, now they are conducted to investigate cost-effectiveness, for questions related to diagnostic or prognostics, genetic studies and of course policy making. Prisma covers a general framework of concepts and topics that can be relevant to any systematic review and not just the initial objective of basic healthcare interventions. Still, there is a copy of enhancement and improvement for specific circumstances. The flow diagram would need interventions and adjustments depending on the source of data and the requirement to conduct a Meta-Analysis.
There is also an availability of an explanatory document for increasing the usefulness of PRISMA. For each of the items on the checklist, the supporting document gives an example of good reporting, a rationale that justifies its inclusion, and also the supporting evidence wherever possible. This supporting document can be of great help to those using PRISMA for the first time and also those who are into teaching systematic review methodology to others.
Key drawbacks of PRISMA
When an investigator creates the PRIMA Flowchart manually there are a number of pain points associated with it. Some of the main challenges are:
1) Time Consumption: Preparing a flow diagram for a systematic literature review is a very time-consuming and tedious task. Because of this sometimes it does not do significant value addition to the activity. The time and expertise of these extremely skilled resources had to be targeted toward the actual analysis of data rather than the time that is wasted on the collection and standardization of data. The extraordinary consumption of time in doing this systematic analysis sometimes brings dawn its quality and applicability.
2) Scope of human error: PRISMA is a manual process that makes the flow diagrams inconsistent. Human errors are common and easy to occur this sometimes brings down the quality of the technique
3) Complex Search activity: When doing the manual process, one must search individual databases such as google scholar, Scopus, PubMed etc to locate relevant articles and then export and compile them into one single data set manually. This can be extremely tedious and complex to do and because of this a lot of PhD scholars and clinical practitioners are not able to find the time and effort to take up the activity.
4) Vast Applicability: The application of PRISMA is quite broad though, but still there are many domains of study where its application is still not commonly accepted and used by investigators. Because of this, its scope gets limited in its applicability
5) Can create a difference of opinion in amongst investigators: Many times in the process when it comes to rejection or inclusion of a study, there may be differences of opinion amongst the researchers and that can sometimes sour their professional relations or harbor grudges that can further impact the quality of their subsequent work together.
Conclusion:
PRISMA is a living document with scope for improvement and revisions for better usefulness and application. The. continuous development of the diagram and its checklist will expand its application and usefulness across different research genres.

Empirical research, mostly used in social sciences, is based on observation and measurement of a phenomenon and derives results from real-time experiences rather than theories. Generally, an empirical paper consists of four components, of which literature review plays a vital role. 

The literature review chapter opens up the study domain, how the field has evolved over time, shows how the research problem under study has been discussed and which are its crucial concepts. 

Hence,while crafting this section, you must be concerned with three major goals: setting the theoretical background, identifying gaps between the existing literature, and describing the key concepts used within the empirical paper. 

Research scholars, especially novices may find the literature review writing process a quite daunting task. To this process an easier one, we have mentioned a few stages involved in the review section crafting process. 

1. The first step includes critical analysis of literature sources. To perform it, select a set of papers obtained from academic portals (depending on your study domain), such as Scopus, Web of Knowledge, EBSCO, JSTOR, SciELO, etc. Remember, portals rank papers by number of citations/relevance, using which you can identify fundamental papers and authors. However, the older the paper has the greater probability of citation. The set of sources collected in this stage is just a preliminary selection which needs to be refined further.
2. After collecting the initial set of sources, do not try to answer the questions immediately. Before doing so, develop ideas as to what can be expected from the current study based on the previous studies. This is followed by finding answers to questions such as:

•  What are the theories included in the existing literature?
•  What do the theories predict the context of your study?
•  What empirical evidences are found in line with the theories?
•  Is there any important debate in the literature? 

Ideally, discussion and comment must be maintained within the paragraphs in this section, without which it gives an impression that you were merely describing the literature and not reviewing it. Experts offering PhD thesis chapters help are at your disposal if you require aid in reviewing the literature. However, upon assessing the sources if the required factors are not found, there is always a scope for further literature analysis. 

A good literature review section must address various requirements, comprising of relevant literature and synthesising it with clarity.

This section consists of key features, including: 

• Rhetoric – The ideas must be presented clearly, coherently, and in a well-articulated text, without making unsupported assertions. 
• Significance –  The review must present the practical and theoretical significance of the research problem. 
• Synthesis –  It should not be limited to a long list of citations, but should summarise and connect relevant references. 

No matter how hard you strive, the initial draft is never going to be a great one. Revise it several times to obtain the final piece of well-crafted literature review chapter. If you need any help in refining, you can always approach professionals offering PhD thesis chapters help.

A critical review of the literature is necessary to help you to develop a thorough understanding of ,and insight into,previous research that relates to your research questions and objectives. Your review will set your research in context by critically discussing and referencing work that has already been undertaken,drawing out key points and presenting them in a logically argued way ,and highlighting those areas where you will provide fresh insights. It will lead the reader into subsequent sections of your project report.

There is no correct structure for a critical review, although it is helpful to think of it as a funnel in which you start at a more general level prior to narrowing down to your specific research question(s) and objectives.

Literature sources can be divided into three categories:primary ,secondary and tertiary.In reality, these categories often overlap. Your use of these resources will depend on your research question(s) and objectives. Some may use only secondary and tertiary literature. For others,you may need to locate primary literature as well.

When planning your literature research you need to:

• Have clearly defined research question(s) and objectives;
• Define the parameters of your search ;
• Generate keywords and search terms;
• Discuss your ideas as widely as possible

Techniques to help you in this include brainstorming and relevance trees .

• Your literature search is likely to be undertaken using a variety of approaches in tandem. These will include
  • Searching using tertiary sources and internet ;
  • Following up reference in articles you have already read;
  • Scanning and browsing secondary literature in your library.
• Once obtained, the literature must evaluated for its relevance to your research questions and objectives using clearly defined criteria .This must include a consideration of each item’s currency. Each item must be read and noted. Bibliographic details,a brief description of the content and supplementary information should also be recorded.
• Care should be taken when writing your literature review not to plagiarise the work of others.