An Overview of the Literature Review Process
Conducting a literature review is a fundamental component of academic research, essential for establishing a solid foundation for any study. Writing literature reviews involves systematically identifying, organizing, synthesizing, and evaluating existing research to address a specific research question. This process not only helps in understanding the current state of knowledge but also in identifying gaps that warrant further investigation. The following overview outlines the key steps involved in the literature review process, breaking it down into simple, distinct stages suitable for graduate students (master’s and doctoral students) and novice researchers.
The literature review methodology outlined in this overview is based on the approach presented in Literature Review Simplified: A Practical Guide for Beginners, Second Edition, which can be purchased on Amazon.
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Identifying Relevant Research
Locating pertinent studies is the initial step in conducting a literature review, whether it’s a traditional narrative review or a systematic literature review. Academic databases like PubMed, JSTOR, Google Scholar, and PsycINFO serve as primary resources for finding peer-reviewed articles, books, and conference proceedings essential for writing literature reviews. Researchers refine their search results using specific keywords and Boolean operators to ensure a comprehensive search. University and public libraries provide additional access to books and journals. Examining reference lists in relevant studies can lead to the discovery of further valuable sources. Grey literature, such as government reports and dissertations, offers essential information that is often overlooked in literature-based research.
Organizing and Managing Sources
Effectively managing a collection of sources is essential in the literature review process. Reference management software like EndNote, Mendeley, or Zotero helps organize citations, generate bibliographies, and annotate sources. Categorizing materials by themes, methodologies, or theoretical frameworks aids in comparing and contrasting studies, which is crucial for constructing a solid literature review and theoretical framework. Creating an annotated bibliography, which includes summaries and evaluations of each source, improves understanding of their relevance and quality.
Synthesizing and Evaluating the Literature
Integrating various research findings into a coherent narrative is the final stage of writing literature reviews. It involves identifying recurring themes, patterns, and discrepancies within the literature. Summarizing key findings, methodologies, and theoretical contributions from each source provides a solid foundation for your literature review and research design. Comparing and contrasting studies to uncover similarities, differences, and possible explanations deepens the analysis. Critically evaluating the sources’ quality, taking into account factors such as research design and sample size, is vital for assessing credibility in literature reviews. Drawing conclusions by synthesizing information, identifying research gaps, and justifying further investigation completes the literature review. A well-formulated review with explicit headings and subheadings enhances readability and comprehension, making literature reviews made easy for readers.
Steps for Conducting Literature Reviews
Drawing inspiration from guides such as The Literature Review: Six Steps to Success, the following sections outline the steps for conducting literature reviews, breaking down the process into simple, distinct stages suitable for graduate students and novice researchers. Each step is graphically presented in its respective section for easy reference and includes practical examples where necessary. The steps involved are:
- Identifying the Research Question
- Defining Inclusion and Exclusion Criteria
- Selecting Databases
- Identifying Key Search Terms
- Developing a Search Strategy
- Retrieving and Screening Articles or Studies from Databases
- Extracting Data from Selected Articles or Studies
- Synthesizing Results
- Assessing Bias Risk and Quality Appraisal
- Reporting the Literature Review
Step 1. Identify the Research Question
Identification of the research question is the initial stage in conducting literature reviews, especially important when considering how to write a literature review. A well-known approach for formulating research questions is the PICOS criteria—Population, Intervention, Comparison, Outcome, and Study design. This method helps structure the question in any research field. Formulating a research question is crucial and often iterative, as asking the right question is key. Research questions can be broad, such as “What type of scientific evidence is available for a specific intervention?” or narrow, like “Do peer-mediated interventions improve social competence in children with learning disabilities compared to a control group?”
Step 2. Define Inclusion and Exclusion (Eligibility) Criteria
Defining the inclusion and exclusion criteria for selecting publications is the second stage in doing a literature review, particularly vital in a systematic literature review. Inclusion criteria are the rules or items that determine which studies to include, while exclusion criteria specify which studies to exclude. These criteria are outlined in the literature review protocol and may be refined during the early stages. Once finalized, they must be strictly followed to ensure the integrity of the review process.
Step 3. Select the Databases
The next stage in conducting a literature review is selecting the databases. This involves identifying the sources from which to retrieve the literature. Different fields have specific electronic databases; for instance, in health sciences literature reviews made easy, databases like PubMed, Medline, and Embase are commonly used. For social sciences, especially for a systematic literature review in social work, databases like PsycINFO and Social Work Abstracts may be more appropriate. Besides established databases, other sources can be used to identify grey literature, white papers, or unpublished work. These sources may include organizational databases or directly contacting researchers for opinions or unpublished work.
Step 4. Identify Key Search Terms
After selecting the databases, the next step in conducting a literature review is to identify the main keywords or search terms. When crafting a research question, it is essential to break it down using the PICOS criteria. This step will help you concentrate on specific components and ensure a systematic approach to your inquiry. For instance, if your research question is: “Does regular exercise decrease the risk of developing type II diabetes in middle-aged individuals compared to those who do not exercise?” Breaking down your research question using the PICOS criteria will direct your search for related literature and help you structure your study in a clear and systematic manner.
Step 5. Develop a Search Strategy for Selected Databases
Developing a search strategy using the final list of keywords and their alternatives is crucial. This involves arranging the keywords in a unique way, combined with other terms, to ensure all relevant articles are retrieved from the target database. Combine identified keywords (search terms) with Boolean operators like “AND,” “OR,” and “NOT” to refine or broaden the search scope. Proper use of Boolean operators is important to obtain the required studies without being overwhelmed by irrelevant results. This ensures you get the desired results from the selected databases, making the process of writing literature reviews more efficient.
Step 6. Retrieve and Screen Search Items from Databases
Retrieving studies from the selected databases after executing the search strategy is the next step. Handling search results manually is difficult, so using reference management software like Mendeley or EndNote is recommended. Once imported, remove duplicates to streamline the process. The screening process involves title screening, abstract screening, and full-text screening to narrow down the studies to those most relevant to your research question.
Step 7. Extract Data from Selected Studies
Once you have finalized the list of studies for your literature review, the next step is to extract data from these selected studies into a data extraction sheet. The data extraction sheet should include all relevant data fields for your literature review, such as study characteristics, research questions, and themes identified during data extraction. This step ensures that all pertinent information is systematically recorded, facilitating the synthesis of results.
Step 8. Synthesize Results
The data collected should be combined coherently and analyzed deeply to help readers better understand the evidence generated in the literature review. The synthesis should include qualitative synthesis and may also involve quantitative analysis. Present the study characteristics in a table, including information such as title, authors, publication year, country of origin, and aims and objectives of the articles. The synthesis of results involves analyzing findings in the form of identified themes or results specific to the objectives and research question.
Step 9. Bias Risk Assessment and Quality Appraisal
Evaluating the risk of bias and appraising the studies for quality is crucial for ensuring transparency and generalizability of the results. The synthesis process should aim to eliminate potential biases in findings. Conduct a quality appraisal of the articles by asking typical questions: Does the publication address a specific question? Did it use valid methods? Are the findings validated and applicable to your context? Critical appraisal evaluates the robustness, value, and trustworthiness of the publications. The CASP (Critical Appraisal Skills Programme) checklist is a commonly used guideline, consisting of 11 questions for the critical appraisal of systematic literature reviews but can be adapted for other study types.
Step 10. Reporting the Literature Review
The final stage of a literature review is to report the methodology and results clearly and concisely for dissemination to stakeholders or target readers. Present the findings based on the structure proposed by the PRISMA guidelines, which are open-source guidelines designed to transparently report findings of systematic reviews and meta-analyses. By adhering to these guidelines, you ensure that your literature review is transparent, comprehensive, and robust, making it valuable to readers. This includes detailing why the literature review was conducted, how it was performed, and what the findings were.
Recommended Book for Writing Literature Reviews
To further aid in writing literature reviews, especially for novice researchers and graduate students, the following book provides detailed guidance:
- Literature Review Simplified: A Practical Guide for Beginners helps demystify the process, making literature reviews approachable for those new to research.