What are the different methods for conducting literature reviews?

Depending on the field and the research goal, writing literature reviews can vary significantly. Independently written literature reviews or those focused on measuring interdisciplinary scientific research may require different approaches compared to other reviews. Depending on the type of review, the focus may be on being highly strict in each step of the process or the review might focus only on summarizing findings. Specialized reviews can be classified into several types, each serving distinct purposes. Here are the most common literature review methods:

Systematic literature review

Performing systematic literature reviews involves a rigorous process of identifying, evaluating, and synthesizing all relevant studies on a given topic. Systematic reviews attempt a high-level synthesis of research findings and require strict tracking of sources and clear inclusion and exclusion parameters. Healthcare research, medical education, and computer science reviews often require this kind of review. A systematic review can be written as a full, stand-alone paper, which provides great value for audiences to understand and evaluate relevant material.

Narrative literature review

These reviews provide a narrative synthesis of the literature, often incorporating the author's perspective. These timely literature reviews are less structured than systematic reviews and instead, they provide a story-like description of the relevant body of knowledge. Narrative literature reviews can offer valuable insights and context for particular scientific developments.

Descriptive literature review

These reviews summarize the current state of knowledge without engaging in critical evaluation. Descriptive reviews provide a broad overview, presenting the findings of existing studies straightforwardly. They focus on summarizing the current state of knowledge, making them suitable for areas with few research papers.

Scoping literature review

Scoping reviews are more exploratory in nature, mapping the breadth and scope of research on a specific topic. They also offer an overview of existing evidence, and identify key concepts and research gaps. Rigorous literature review efforts start with a clear research question and a detailed protocol, conducting exhaustive searches across multiple databases. Selected studies are systematically screened, and data extraction focuses on study characteristics and findings. The results highlight patterns and themes in the literature, concluding with a report that maps the research landscape and identifies areas needing further investigation, thus identifying research priorities.

Realist literature reviews

Realist reviews aim to understand how complex social interventions or programs work in different contexts. Grounded in a theoretical framework, these reviews aim to use iterative and purposive searches to capture a wide range of relevant sources. Each study is critically appraised for its quality and relevance, with data extracted on contexts, mechanisms, and outcomes to identify specific factors influencing the effectiveness of the studied interventions. The synthesis process explains the varied results, validated through stakeholder feedback and expert consultations. The final report presents a detailed and transparent account of the methods, findings, and implications. This makes it a timely literature review for understanding social interventions and programs, informing public policy and practice in public health, social sciences, and education.

Critical literature review

Critical reviews evaluate and synthesize existing research on a topic to provide a comprehensive understanding, identify gaps, and propose new perspectives. Instead of only summarizing existing literature, researchers reflect on and evaluate implicit assumptions, offering their own interpretations or perspectives on the topic. A critical review starts with a defined scope and questions, followed by an exhaustive search of relevant sources. Each study is critically appraised for quality and relevance, and the synthesis integrates findings to highlight key themes and gaps. This type of review challenges existing assumptions and suggests new theoretical perspectives, concluding with a structured report that provides a nuanced understanding of the topic.

Meta-analysis literature review

Meta-analysis reviews statistically combine results from multiple studies to identify overall trends and effect sizes. They begin with a clear research question and inclusion criteria, followed by a comprehensive and systematic search of databases. Data extraction focuses on study characteristics, effect sizes, and outcomes, with statistical methods used to aggregate and analyze the data. The findings, presented with detailed tables, figures, and narrative synthesis, discuss the implications and limitations, providing robust and generalizable conclusions. This type of review is particularly relevant in fields with a high number of quantitative studies, such as medicine, evolutionary ecology, and psychology.

Umbrella literature review

Umbrella reviews synthesize evidence from multiple systematic reviews and meta-analyses to provide an overarching understanding of a broad topic. Starting with clear scope and objectives, they identify relevant reviews and critically appraise their quality and relevance. Data extraction focuses on study characteristics and findings, integrating them to identify consistent patterns and overall conclusions. The final report summarizes the evidence comprehensively, discussing implications for practice and future research, offering a high-level synthesis valuable for decision-makers and researchers. This type of review often results in many reviews being integrated into one comprehensive review, such as annual reports or white papers.