Primary vs Secondary Sources in Research: Differences and Examples

Understanding the distinction between primary and secondary sources is fundamental to conducting rigorous research. A primary source is original material created at the time of the event or phenomenon being studied, such as a laboratory experiment, survey data, historical document, or interview. A secondary source is an interpretation, analysis, or

How to Write a Discussion Section: Interpretation, Limitations and Implications

The discussion section of a research paper is where you explain what your results mean, how they relate to existing evidence, what limitations affect their interpretation, and what implications they have for theory, practice, or future research. Unlike the results section, which reports the data, the discussion interprets the data.

How to Write a Research Paper Introduction: Structure and Examples (CARS Model)

The introduction of a research paper establishes the context for the study, identifies the research gap, and presents the research question or objectives that the study will address. It is the first substantive section the reader encounters after the abstract, and its purpose is to convince the reader that the

How to Write a Research Rationale: Definition, Examples & Justification

A research rationale is the section of a proposal, thesis, or manuscript that explains why the study is necessary and what contribution it will make to existing knowledge. It answers the question every reviewer and reader will ask: why does this study matter? The rationale connects the identified research gap

Publication Bias: Funnel Plots, Egger's Test + Prevention

Publication bias occurs when the results of a study influence whether it is published, creating a systematic distortion in the available evidence. Studies with statistically significant, positive, or novel findings are more likely to be published than studies with null, negative, or inconclusive results. When a systematic review or meta-analysis

Effect Size Explained: Cohen's d, Hedges' g, OR + RR Guide

Effect size is a quantitative measure of the magnitude of a phenomenon, relationship, or difference observed in a study. While statistical significance tells you whether an effect exists (whether the null hypothesis can be rejected), effect size tells you how large that effect is and whether it matters in practice.

How to Conduct a Narrative Review: Step-by-Step Guide With Examples

A narrative review is a type of literature review that synthesizes and interprets existing research on a topic by organizing findings thematically rather than following the strict, protocol-driven methodology of a systematic review. Narrative reviews are the most common type of review article in academic publishing because they allow authors

How to Write the Background of a Study: Step-by-Step Guide with Examples

The background of a study is the opening section of a research paper or thesis that establishes what is already known about the topic, identifies what remains unknown, and explains why the current study is needed. It provides readers with enough context to understand the research problem without requiring them

How to Assess Risk of Bias: RoB 2, ROBINS-I + QUADAS-2

Risk of bias assessment is the process of evaluating whether the design, conduct, or analysis of a study may have distorted its results. Every systematic review includes a risk of bias assessment because flawed studies can produce misleading conclusions, and without a formal evaluation, reviewers have no structured way to

Scoping Review vs Systematic Review: Differences With Examples

A scoping review and a systematic review are both forms of evidence synthesis that follow structured, transparent methodologies, but they serve fundamentally different purposes. A scoping review maps the breadth and nature of available evidence on a broad topic, while a systematic review synthesizes and appraises evidence to answer a

How to Conduct a Scoping Review: Steps + Examples (2026)

A scoping review is a type of evidence synthesis that maps the breadth and nature of research activity on a broad topic, rather than answering a narrow clinical question like a systematic review does. Researchers use scoping reviews to identify knowledge gaps, clarify key concepts, examine how research is conducted

PRISMA Guidelines: Step-by-Step Workflow With Examples

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is an evidence-based reporting guideline that helps researchers transparently document every phase of a systematic review. The PRISMA 2020 statement includes a 27-item checklist organized into seven sections and a four-phase flow diagram that tracks how records move from identification through