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Systematic Reviews: Literature Search

A Synthesis and Evaluation of existing evidence

Introduction

A literature search for a systematic review involves a methodical and comprehensive process of identifying, retrieving, and evaluating relevant studies on a specific research topic.

  1. Definition:

    • A literature search for a systematic review is a systematic and rigorous process of identifying, retrieving, and evaluating all available evidence relevant to a specific research question or topic.
    • It involves systematically searching multiple databases, gray literature sources, and trial registries to ensure comprehensive coverage of the literature.
    • The search is conducted following predefined criteria and strategies to minimize bias and ensure transparency and reproducibility.
  2. Objectives:

    • Identify Relevant Studies: The primary objective is to identify all relevant studies that address the research question or objective of the systematic review.
    • Minimize Bias: By conducting a comprehensive search across multiple sources, the goal is to minimize selection bias and ensure that all available evidence, including both published and unpublished studies, is considered.
    • Ensure Transparency and Reproducibility: A systematic literature search aims to document the search process in detail, including search strategies, databases searched, and inclusion/exclusion criteria, to ensure transparency and reproducibility of the review.
    • Support Evidence-Based Decision Making: By synthesizing the findings of relevant studies, the systematic review aims to provide a comprehensive and unbiased summary of the available evidence to inform decision making, policy development, or future research directions.
  3. Scope:

    • Inclusion Criteria: The scope of the literature search is defined by the inclusion criteria, which specify the types of studies, participants, interventions, outcomes, and study designs considered relevant to the systematic review.
    • Exclusion Criteria: Similarly, exclusion criteria delineate the boundaries of the search by specifying the types of studies or sources that will be excluded from consideration (e.g., studies with high risk of bias, non-English language studies).
    • Time Frame: The literature search typically covers a specific time frame relevant to the research question, ensuring that the review captures the most up-to-date evidence while also considering the historical context of the topic.
    • Geographic and Language Coverage: The scope may also specify geographic regions and language restrictions, depending on the research question and available resources.
    • Gray Literature and Unpublished Studies: The scope may include searches for gray literature sources, such as conference proceedings, dissertations, government reports, and clinical trial registries, to ensure comprehensive coverage of the evidence base.