Literature Review Methods

Conducting a literature review is essential for any research project. It provides a comprehensive understanding of existing knowledge and identifies gaps that need further exploration. Various methods, each with its associated methodologies, cater to different research needs and objectives.

While the same underlying literature review process is almost always followed, the research methodology guiding each literature review can emphasize different aspects, ranging from the specific methods employed to the driving purpose of the review. As literature reviews are most often included as a sub-section within a broader empirical study, one of the most common approaches to literature reviews is the narrative review, such that researchers provide a qualitative summary of relevant literature and integrate their interpretations to offer valuable context and depth. In contrast, when researchers aim to methodically synthesize a body of research to inspire future research, they might write a full-paper literature review adopting a systematic literature review approach to produce a rigorous and reproducible analysis.

Systematic and narrative review processes are among the most common literature review methods employed by researchers. Systematic reviews emphasize in the methods driving the literature review while narrative approaches emphasize on the purpose of the literature review. Within these two overarching foci, a variety of additional literature review methods are also available to researchers. For instance, researchers aiming to robustly integrate findings across multiple empirical studies can conduct a meta-analysis to statistically analyze emergent significant findings. If various systematic and meta-analytic reviews already exist within an area of inquiry, then researchers may conduct an umbrella review to synthesize findings across different reviews.

When researchers are writing literature reviews to realize a specific purpose, they can choose among various methods suited to their goals. For example, when researchers want to simply document the scope of research on a given topic, they can conduct a descriptive review to outline the current state of knowledge, which is particularly valuable in fields where research is still emerging. Alternatively, if researchers want to identify key concepts and insights within a burgeoning stream of research, they could conduct a scoping review to flexibly explore novel or underdeveloped topics. Some researchers may specifically aim to challenge taken-for-granted assumptions, in which case they can follow critical literature review methods. Finally, researchers may also conduct a realist review when their focus is on assessing specific interventions or programs in an area of research.

Each type of literature review has unique strengths and applications. Choosing the right review method is crucial to the research question and goals. A good literature review should integrate empirical findings with theoretical insights. It should provide a comprehensive critical analysis of the published literature. Researchers need to carefully choose their research design and write a literature review that addresses specific objectives. This involves employing qualitative methods, analyzing data meticulously, and constructing review articles that contribute meaningfully to the field.

Methods for conducting literature reviews

There are several different review methods used in academic research, each with its specific purpose, methodology, and application. Here is an overview of the most common review methods:

Systematic literature reviews

A systematic literature review is a rigorous approach to reviewing and synthesizing existing research on a particular topic. It aims to provide a comprehensive summary of the evidence, identify gaps, and inform policy or practice. The systematic review method starts with a clearly defined research question. Researchers then conduct a systematic search of relevant literature and follow a predefined protocol. The selection process is transparent, reproducible, and focuses on inclusion and exclusion criteria. Each selected study undergoes a quality assessment, and researchers can further synthesize findings using qualitative or quantitative methods. These reviews are valuable for their thoroughness and reproducibility. They provide a solid foundation for evidence-based decision-making. In healthcare research, for instance, systematic reviews evaluate healthcare interventions by reviewing randomized controlled trials and other primary research studies. Despite being time-consuming, their ability to offer high-level empirical evidence makes them essential in fields like social sciences and healthcare. Reporting systematic reviews involves presenting the methods and findings in a detailed, transparent manner, often following guidelines such as PRISMA to ensure clarity and reproducibility.

Narrative literature reviews

A narrative literature review offers a summary and interpretations of the literature on a specific topic. Unlike systematic reviews, narrative reviews are more flexible and less structured. They aim to provide an overview of the current state of knowledge, identifying major themes, debates, and trends. This method is often employed in traditional literature reviews. Researchers conducting a narrative review start with a broad research question. They search for relevant articles but do not necessarily follow a predefined protocol. This flexibility allows them to explore various perspectives and theories. The narrative review synthesizes the findings, often highlighting strengths and weaknesses in the literature. It provides context and background, helping readers understand the evolution of the research topic. While narrative reviews may be seen as less rigorous than systematic reviews, they offer valuable insights. They are particularly useful for exploring new or emerging topics where little structured research exists.

Meta-analysis

A meta-analysis systematically combines the results of multiple scientific studies addressing the same question to derive a more precise and comprehensive understanding of a particular field or issue. A meta-analysis enhances statistical power and resolves uncertainties that may arise from individual studies due to small sample sizes or differing methodologies. This technique is often used in health services research to evaluate health care interventions and is complemented by qualitative systematic reviews and qualitative research to assess the broader context and implications of findings. Meta-analyses offer a higher level of evidence on the efficacy, effectiveness, or impact of the subject under investigation. They are particularly valuable for review papers that aim to address narrow research questions within a specific domain.

Umbrella literature review

This kind of review compiles evidence from multiple systematic reviews and meta-analyses on a specific topic. It aims to provide a comprehensive overview of the evidence and synthesize findings across different reviews. Researchers conducting an umbrella review start with a broad research question. They perform a systematic search and selection of systematic reviews and meta-analyses. The review synthesizes their findings, providing a comprehensive overview of the evidence. Umbrella reviews are valuable for providing a broad perspective on a topic. They synthesize high-level evidence, offering a comprehensive overview of the research. However, their reliance on existing reviews means that the quality of the included reviews affects the overall findings.

Descriptive literature reviews

Descriptive literature reviews aim to summarize and explain the current state of knowledge on a particular topic without the stringent criteria of systematic reviews. Their primary purpose is to provide a comprehensive overview of existing research, identifying patterns, themes, and gaps in the literature. Key characteristics include a broad search strategy, a narrative synthesis of findings, and a focus on presenting a descriptive, as opposed to an interpretive, account of the available research. Descriptive literature reviews are useful in fields where research is still emerging, offering a foundational understanding for further study. They help researchers and practitioners grasp the scope of the topic, inform future research directions, and provide context for empirical studies by compiling and analyzing the published literature.

Scoping literature reviews

A scoping review provides a preliminary assessment of the potential size and scope of available research literature on a particular topic. It aims to identify the nature and extent of research evidence, clarify key concepts, identify themes, and map out the available literature. This method is ideal for identifying research gaps and refining research questions. To conduct a scoping review, it is recommended to start with a broad research question. The literature search and selection of studies do not have to include a quality assessment or synthesis of findings. The primary goal is to map the existing literature and identify gaps. Scoping reviews are valuable for exploring new research areas and identifying research gaps. They provide a comprehensive overview of the existing literature which helps researchers refine their research questions and design future studies.

Critical literature reviews

A critical review involves a detailed analysis and critique of existing literature. It highlights strengths, weaknesses, and gaps in the research. The primary goal is to provide a critical perspective on the literature, challenging existing assumptions and opening new avenues for future research. Researchers conducting a critical review start with a clear research question. They conduct a systematic search and selection of studies, followed by a rigorous analysis of their quality and underlying assumptions. The review synthesizes the findings, offering a critical perspective on the existing literature. Critical reviews are valuable for their in-depth analysis and critical insights. They help researchers identify implicit assumptions or dominating discourses in the literature, providing a foundation for future research. However, as their focus is on criticizing dominant assumptions or trends, authors need to carefully craft their writing to present both compelling and constructive arguments.

Realist literature reviews

A realist review is a theory-driven approach to synthesizing evidence. It focuses on understanding how and why interventions work in specific contexts. The primary goal is to develop and refine program theories, explaining the mechanisms underlying an intervention's success or failure. Researchers conducting a realist review start with a broad research question. They use an iterative search process, guided by realist principles. Data extraction and synthesis involve identifying the underlying mechanisms, contexts, and outcomes. The review aims to provide a nuanced understanding of the intervention's effectiveness. Realist reviews are valuable for their focus on context and mechanisms. They help policymakers and practitioners understand why interventions work in some settings but not others. However, their complexity and need for expert judgment can make them challenging to conduct.

Conclusion

Conducting a literature review is a fundamental step in the research process. It provides a thorough understanding of the existing body of knowledge. Different types of literature reviews serve various purposes and cater to diverse research needs. Writing a literature review requires careful consideration of the research question, methodology, and objectives. This ensures that the final review is a valuable resource for researchers and practitioners alike. Each type of literature review contributes uniquely to the research landscape. Therefore, choosing the appropriate method is essential when writing a literature review.