Literature review

• A literature review is a critical assessment of published literature on a particular topic.
• Main goal of a literature review is synthesis of knowledge scattered into a single representation
• phases of literatures review are classification, comparison, and evaluation of existing knowledge.
• Contributions of a literature review

  -       Identifying research gaps and proposing a research agenda

  -       Assessing outcomes of interventions through systematic reviews and meta-analysis

  -       Providing taxonomies, typologies, and conceptual frameworks for classifying research findings

  -       Proposing new ways of thinking about the topics addressed
• Literature review can be used to identify trends or patterns in the data that may not have been apparent from individual studies alone. This can lead to more comprehensive understanding of the phenomenon being studied.
• Critical approach: analysis, synthesis, comprehension and knowledge.
• Analysis: Breaking up data into smaller units and selecting/differentiating them
•   Synthesis: Integrating, combining, and reorganizing smaller units to identify relationships. Going beyond summarizing sources, defining major themes, strengths, weaknesses, and gaps
• Comprehension: Understanding, interpreting, and explaining the outcome of the review. Comparing and contrasting existing views represented in the included studies.
• Knowledge: Creating new insights by applying critical thinking skills to analyze and interpret information. Developing recommendations based on evidence gathered during the review process.
• Narrative reviews: undefined methods of searching, broad aim, no structured method, subjective quality assessment.
• Systematic reviews: explicit rigorous methods of searching, narrow focus, specific review question, rigorous search and selection, objective quality assessment, tabular analysis and synthesis, methodological report.
• The SALSA Framework is an approach that can be used to guide systematic reviews of literature. It consists of four stages: Search, Appraisal, Synthesis, Analysis.
• Search - This stage involves identifying relevant research through a comprehensive search strategy using databases, reference lists, and other resources. The goal is to find all available evidence related to the research question or topic being reviewed.
• Appraisal - In this stage, the quality of the identified studies is evaluated using predefined criteria. This helps ensure that only high-quality studies are included in the final review.
• Synthesis stage involves organizing data from selected articles into tables or charts, analyzing them, and drawing conclusions.
• Analysis - Finally, the results of the synthesis are interpreted and discussed in light of existing knowledge and theory. Conclusions are drawn about the overall impact of the evidence and any implications for practice or further research.
• Configurative reviews interpret and understand a given topic, seeking enlightenment through new ways of understanding
• Aggregative reviews collect empirical data to describe and test predefined concepts seeks evidence to inform decision making
• With a Systematic review, the review question does not have to be predefined and can be adjusted iteratively as articles are read. The review question may start too narrow or too broad and can be adjusted based on the search results
• in a systematic review, inclusion and exclusion criteria should be defined and strengths and weaknesses of each included article should be assessed
• A methodological section should be included in the final report, describing and justifying the steps taken and decisions made. A methodological appendix can be included for additional details
• Narrative reviews summarize the existing knowledge on a topic in a comprehensive and descriptive manner
• Scoping Review: A review designed to identify the extent and nature of research on a specific topic, often used to clarify key concepts and gaps in the literature.
• Systematic Review: A rigorous review that follows a predefined methodology to synthesize and critically appraise the existing literature on a focused research question
• Meta-analysis: A statistical technique that combines the results of multiple studies to generate a more robust and quantitative summary
• Aggregative reviews focus on understanding the empirical situation and testing theory. Important to include all relevant work and avoid bias in aggregative reviews
• Configurative research aims to generate theory and deepen understanding of a topic. Review questions are key and iterative in the literature review methodology
• PICO format is useful for aggregative review objectives

  -       Patient problem/population

  -       Intervention

  -       Comparison

  -       Outcome
• SPIDER question format is useful for qualitative and mixed methods research reviews. Spider question format is useful for search strategies in qualitative and mixed methods reviews.

  -       Sample

  -       Phenomenon of Interest

  -       Designs

  -       Evaluation

  -       Research type
• PICO focuses on intervention or exposure, while SPIDER focuses on phenomenon of interest
• PICO is for quantitative research studies, SPIDER can be used for various research types
• PICO is commonly used in clinical research to structure questions related to interventions and outcomes, while SPIDER is employed in qualitative and social science research to structure questions that explore experiences, perceptions, and social phenomena.
• Using a conceptual framework is not necessary for most aggregative studies. It is common for a configurative review.
• Search string is a list of key search words used to identify relevant papers
• * can be used to include all words starting with the same prefixes
• common mistakes:

  -       Getting distracted by reading too many relevant papers and losing focus

  -       Not every analysed article needs to be included in the review

  -       Limiting the review to a sequential summary of previous research is not a literature review
•  Too many results 

  •  add another search term using “AND” 
  •  use proximity/wildcard operators
  • Use phrase searching
  •  Use limits
• Too little results

  • Remove limits and/or search terms
  • Add synonymous (using OR)
  • Use indexers/descriptors (e.g. MeSH terms in pubmed)
  • Check references
  • Check citations
  • Check core authors 
  • Check core journals