Why do literature review

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Last updated: April 8, 2026

Quick Answer: A literature review systematically examines existing scholarly works to identify research gaps, establish theoretical frameworks, and avoid duplication. It typically analyzes 50-200+ sources depending on field and scope, with systematic reviews following PRISMA guidelines established in 2009. Literature reviews help researchers build on existing knowledge while identifying where new contributions are needed.

Key Facts

Literature reviews typically analyze 50-200+ scholarly sources depending on discipline and scope
Systematic reviews follow PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines established in 2009
Scoping reviews were formalized as a methodology by Arksey and O'Malley in 2005
Literature reviews can reduce research duplication by 15-30% according to multiple studies
The average literature review in social sciences covers 75-100 sources published over 10-15 years

Overview

A literature review is a comprehensive survey of scholarly sources on a specific topic, providing an overview of current knowledge and identifying relevant theories, methods, and gaps in existing research. The practice dates back to ancient scholarship but became formalized in the 20th century with the growth of academic publishing. In 1972, Cooper established foundational taxonomy for literature reviews, categorizing them by focus, goal, perspective, coverage, organization, and audience. The digital revolution of the 1990s transformed literature reviews through databases like PubMed (established 1996) and Google Scholar (launched 2004), enabling access to millions of sources. Today, literature reviews are essential components of academic research, thesis writing, grant proposals, and evidence-based practice across all disciplines from medicine to humanities.

How It Works

Conducting a literature review follows a systematic process beginning with defining research questions and establishing inclusion/exclusion criteria. Researchers search academic databases using Boolean operators and controlled vocabulary, typically reviewing titles/abstracts of hundreds of potential sources before selecting 50-200+ relevant works. The analysis involves synthesizing findings, identifying patterns and contradictions, and evaluating methodological quality. Different review types serve specific purposes: systematic reviews use rigorous protocols to answer focused questions; scoping reviews map key concepts and evidence types; narrative reviews provide broad overviews. Tools like citation management software (EndNote, Zotero, Mendeley) help organize sources, while PRISMA flow diagrams document the selection process. Quality assessment often uses established checklists like CASP for qualitative studies or Cochrane Risk of Bias tools for clinical trials.

Why It Matters

Literature reviews have significant real-world impact across sectors. In healthcare, systematic reviews inform clinical guidelines that affect millions of patients, with Cochrane reviews alone influencing treatment decisions worldwide. In policy-making, literature reviews provide evidence bases for legislation and regulations. For researchers, they prevent duplication, saving an estimated $100+ million annually in wasted research funding. Literature reviews also accelerate innovation by identifying knowledge gaps where new discoveries are needed most. In education, they ensure curricula reflect current evidence. The growing emphasis on evidence-based practice in business, healthcare, and government makes literature reviews increasingly vital for decision-making, with organizations spending substantial resources on knowledge synthesis to stay competitive and effective.