Extended Essay: Literature Review and Source Evaluation

Your Extended Essay isn't just a long essay; it's a formal piece of scholarly research. The strength of your entire argument rests upon the foundation of the sources you choose. Mastering the process of finding, evaluating, and synthesizing academic evidence is what separates a competent essay from an exceptional, inquiry-driven piece of original analysis.

Strategic Source Discovery: Building Your Research Toolkit

The first step is moving beyond simple Google searches and into the world of academic research. Your goal is to build a comprehensive, high-quality bibliography—a list of sources that will underpin your investigation. This requires using the right tools and understanding the different types of evidence available to you.

Begin with your school or local library's subscription databases. Resources like JSTOR, ProQuest, and your library's specific subject-area portals are gateways to peer-reviewed academic journals, books, and primary source collections. Using precise keyword searches is crucial. Start broad with your research question, then narrow down by combining terms (using AND, OR, NOT) and reviewing the "subject terms" or "descriptors" attached to useful articles you find. These terms are the academic language for your topic and will lead you to more relevant material.

You must also distinguish between primary and secondary sources. A primary source is original, first-hand evidence directly related to your topic—a novel, a historical treaty, experimental data, or an interview you conduct. A secondary source is scholarly work that analyzes, interprets, or comments on primary sources or events—a literary criticism article, a historian's book, or a scientific review paper. A strong EE effectively weaves both together: you use primary sources as your core evidence and secondary sources to contextualize your analysis, show engagement with existing scholarship, and strengthen your argument's credibility.

Evaluating Reliability and Relevance: The Critical Appraisal

Finding a source is only half the battle; you must then rigorously assess its value for your specific essay. Evaluation has two interconnected pillars: reliability (authority and credibility) and relevance (fit for purpose).

To assess reliability, interrogate every source. For authors, check their institutional affiliation, academic credentials, and publication history in the field. For publications, determine if it’s a respected, peer-reviewed academic journal or a reputable university press. Examine the date of publication—is the information current, or is an older source considered a seminal work in the field? Scrutinize the source’s purpose and potential bias. Is it intended to inform, persuade, or sell? Who funded the research? A corporate-funded study on climate change, for instance, requires more careful scrutiny than one published in Nature.

Relevance is about precision. A source can be highly reliable but useless if it doesn't directly connect to your research question. Ask yourself: Does this source provide essential background, a key theory, specific data, or a counter-argument I must address? Does it help define my topic's scope or methodology? Create an annotated bibliography as you research, writing a few sentences for each source summarizing its main argument and specifically noting its relevance to your EE. This practice prevents you from collecting interesting but tangential material and forces you to think critically about each source’s role from the start.

Synthesis and Argument Construction: From Summary to Conversation

The most common pitfall in student research is the "source dump"—stringing together summaries of what different authors say without building your own argument. Synthesis is the active process of combining information from multiple sources to create new insights and support your unique thesis. Your voice must be the conductor of this scholarly orchestra.

Move beyond mere summary by looking for connections between your sources. Do two historians disagree on the cause of an event? Does a sociological theory help explain patterns in your primary literary text? Your job is to highlight these agreements (synthesis), disagreements (contrast), and gaps. Use phrases like "Building on X's work, Y argues that..." or "While Smith focuses on economic factors, Jones introduces the critical element of social perception..." This demonstrates you are engaging in a scholarly conversation.

Your entire literature review should be organized thematically or methodologically around the key points of your argument, not as a list of sources. Each paragraph should have a topic sentence that makes a claim supporting your thesis, followed by integrated evidence from your evaluated sources, and your analytical commentary explaining how this evidence proves the claim. This approach ensures you are using primary and secondary evidence effectively, where primary sources are the raw material of your analysis and secondary sources provide the interpretive frameworks and scholarly context.

Common Pitfalls

Over-Reliance on a Single Source or Type of Source: Basing your entire argument on one book or using only websites creates a fragile foundation. Your EE must demonstrate a breadth of research. Similarly, using only secondary sources turns your essay into a report on other people's ideas, while using only primary sources lacks scholarly context. Balance is key.

Superficial Evaluation (The "Looks Academic" Trap): Just because a PDF has footnotes or is hosted on a .edu domain does not automatically make it a rigorous academic source. Students often mistake university lecture notes or undergraduate papers for peer-reviewed scholarship. Always apply the full reliability criteria (authority, publication venue, peer-review, bias).

Quoting Instead of Integrating: Dropping in long, unexplained quotations is not analysis. Every quote must be introduced, its relevance explained, and then analyzed in your own words. Paraphrase and summarize where possible, reserving direct quotes for particularly powerful or definitive statements that need to be presented verbatim.

The Disconnected Literature Review: A review that is merely a prelude to your "real" analysis, never referenced again, is a missed opportunity. The sources and theories you discuss in your review must be actively used in your subsequent analysis chapters. Weave key authors and concepts throughout your essay to show a consistent, engaged dialogue with existing research.

Summary

• Source discovery is strategic: Utilize academic databases and libraries with precise keyword searches, and consciously build a collection that includes both primary (direct evidence) and secondary (scholarly analysis) sources.
• Evaluation is a two-step filter: Critically appraise every source for its reliability (authority, credibility, bias) and its relevance to your specific research question and argument.
• Synthesis is the core scholarly skill: Move beyond summarizing individual sources to comparing, contrasting, and connecting them, using their insights to build and support your own original argument.
• Avoid foundational weaknesses: Ensure your argument is not dependent on a single source, rigorously evaluate everything you find, integrate evidence analytically rather than just quoting it, and connect your literature review directly to your analysis.
• Your voice is paramount: You are not reporting on sources; you are orchestrating them. Your analysis and argumentative thesis must be the driving force that determines how every source is used.