A literature review collects the key sources on a topic and discusses them in conversation with each other, which the Purdue OWL calls synthesis (Purdue OWL). It can be a section of a larger paper or a standalone assignment. Either way, its job is not to list what you read; it is to show what the research as a whole says about your question.
What is a literature review, and how is it different from a research paper?
The UNC Writing Center draws the line clearly: in a research paper you use the literature as a foundation and support for a new insight that you contribute, while a literature review focuses on summarizing and synthesizing the arguments and ideas of others (UNC Writing Center). In class, a review is often assigned to help you learn a field, see who works on a topic and find gaps that could become a project of your own (Purdue OWL).
| Literature review | Research paper | |
|---|---|---|
| Main goal | Map what is known about a question | Argue a thesis or report new findings |
| Role of sources | They are the subject | They support your argument |
| Typical structure | Introduction, themed body sections, conclusion with gaps | Introduction with thesis, body, conclusion |
| Your contribution | The synthesis: patterns, debates, gaps | A claim or result of your own |
If your assignment is a research paper with a literature review section, the review part is usually shorter and leads into your own question or argument. Start with how to write a research paper for the overall structure.
What are the steps to write a literature review?
Define the scope and the question
Write down the question the review answers, the time span, and what is in or out (population, setting, type of study). A narrow scope makes the search manageable and the review coherent.
Search systematically and keep a log
Search two or three databases with the same keyword combinations, note each search and its number of results, and follow the reference lists of the best sources. See how to find scholarly sources.
Screen and select
Read titles and abstracts first, then full texts of the promising ones. Keep sources that address your question directly; note why you left the others out.
Fill a synthesis matrix as you read
One row per source, one column per thing you want to compare: aim, method and sample, key findings, the themes it speaks to, limitations. Record page numbers for anything you might quote.
Find the patterns
Read the matrix by column, not by row. Where do sources agree? Where do they conflict, and is the conflict explained by method, sample or date? What has no one studied yet?
Choose a structure and outline
Organize the body chronologically, thematically or by method, and outline one section per theme, period or method with the sources that belong to it.
Write synthesis paragraphs, then the introduction and conclusion
Open each paragraph with a claim about the literature, support it with several sources, and explain what the pattern means. Write the introduction and conclusion last, and cite every source as you go.
What is a synthesis matrix?
A synthesis matrix is a table with one row per source and one column per point of comparison. It turns a pile of notes into something you can read across, which is where synthesis comes from. Copy this template into a spreadsheet or your notes:
| Source | Aim or question | Method and sample | Key findings | Theme 1 | Theme 2 | Limits and gaps |
|---|---|---|---|---|---|---|
| Author (year), p. | What the study asked | Design, who, how many, where | Main results in your words | What it says about theme 1 | What it says about theme 2 | What it can't show |
| ... |
Here is a filled-in example for a review question about whether banning phones during class improves learning in high schools. The three studies are hypothetical, written to show how the matrix works; in your matrix, each row is a real source with its citation.
| Source | Aim | Method and sample | Key findings | Achievement | Attention and behavior | Limits |
|---|---|---|---|---|---|---|
| Study A | Effect of a school-wide ban on test scores | Before-and-after comparison, four schools, two years | Small gain in test scores, mostly among lower-achieving students | Small positive | Not measured | No comparison schools |
| Study B | Teachers' view of distraction after a ban | Interviews with 30 teachers | Teachers report fewer interruptions | Not measured | Positive (reported) | Self-report only |
| Study C | Ban vs. no ban, matched schools | Quasi-experiment, 20 schools | No overall change in grades; fewer discipline referrals | No effect | Positive (records) | One district |
Reading down the columns already gives you the structure of the review: achievement effects are mixed, while attention and behavior effects point the same way across very different methods.
What is the difference between summary and synthesis?
The UNC Writing Center defines a summary as a recap of the important information of a source, and a synthesis as a re-organization of that information that can offer a new interpretation or trace the debates in a field (UNC Writing Center). Most reviews combine both, but the synthesis is what makes a review good. Using the hypothetical studies above:
Summary (one source per paragraph):
Study A compared test scores in four schools before and after a phone ban and found a small gain, mostly among lower-achieving students. Study B interviewed 30 teachers, who said there were fewer interruptions after the ban. Study C compared 20 matched schools and found no change in grades but fewer discipline referrals.
Synthesis (sources compared around a claim):
Evidence that phone bans raise achievement is mixed, but evidence that they improve classroom behavior is consistent. The only study with comparison schools (Study C) found no change in grades, which suggests that the gain in Study A may reflect other changes over the same two years. By contrast, both teacher reports (Study B) and school discipline records (Study C) point to fewer disruptions, a pattern that holds across two very different methods. Whether calmer classrooms eventually translate into learning gains remains untested.
The synthesis paragraph opens with a claim about the literature, compares the sources, explains the disagreement, and ends with a gap. A quick test from the Purdue OWL: look at the in-text citations in each paragraph. If each paragraph cites only one source, you are probably summarizing (Purdue OWL).
How do you organize a literature review?
The UNC Writing Center describes three common ways to organize the body: chronologically, thematically or methodologically (UNC Writing Center).
| Structure | Organized by | Use it when | Example sections (phone-ban review) |
|---|---|---|---|
| Chronological | When sources were published or the periods they cover | The field changed clearly over time | Early studies on phones and attention; studies after school-wide bans spread; recent district-level evaluations |
| Thematic | Topics or questions, even if time still matters inside each | Sources address several distinct issues | Achievement; attention and behavior; student well-being; enforcement |
| Methodological | How researchers studied the topic | Different methods lead to different findings | Before-and-after studies; matched-school comparisons; interviews and surveys |
Thematic structure is the most common choice for class assignments, because it makes synthesis almost unavoidable: each section has to bring several sources together around one issue.
What goes in the introduction and conclusion?
The UNC Writing Center lists three parts: an introduction that gives the topic and the organizing pattern, a body that discusses the sources, and conclusions about what you have drawn from the literature and where the discussion could go next (UNC Writing Center). The Purdue OWL adds that in a standalone review the introduction and conclusion take more space, and may describe how you found and selected sources (Purdue OWL).
- Introduction: the question, why it matters, the scope (years, populations, types of study) and how the review is organized.
- Conclusion: what the research agrees on, where it disagrees and why, the main gaps, and what that means for practice or for the next study.
Common literature review mistakes
- Annotated bibliography in paragraph form: one paragraph per source, in the order you read them.
- No claims of your own: every paragraph starts with an author's name instead of a point about the literature.
- Uneven coverage: three paragraphs on the first source you found, one sentence on the strongest one.
- Ignoring disagreement: leaving out studies that don't fit, instead of explaining why results differ.
- Missing citations: every finding needs an in-text citation, with a page number for quotations. See APA in-text citations.
- Tense drift: APA Style recommends the past tense or the present perfect when you discuss other researchers' work, for example "Martin (2020) addressed" or "Researchers have studied" (APA Style). Avoid switching tenses when you describe the same study.
If you are unsure whether a source is primary or secondary, and how that matters for a review, see primary vs secondary sources.
Frequently asked questions
How many sources should a literature review have?
It depends on the assignment and the field. Check the instructions first; the review should cover the key sources on your question, which matters more than reaching a number.
Can a literature review have a thesis?
Yes. Many good reviews make a claim about the literature, for example that the evidence for an effect is weaker than often assumed. That claim organizes the review.
What is the difference between a literature review and an annotated bibliography?
An annotated bibliography discusses each source separately. A literature review groups sources and compares them, so the paragraphs are about themes, debates and gaps rather than single sources.
Should a literature review be in chronological order?
Only if the field changed clearly over time. Thematic organization is more common for class assignments because it groups sources around shared questions.
What tense is used in a literature review?
In APA Style, the recommended tenses for discussing other researchers' work are the past ("Martin (2020) addressed") or the present perfect ("Researchers have studied"). Other styles and fields may differ, so check your instructor's guidance.
Sources
- Purdue Online Writing Lab. Writing a Literature Review. owl.purdue.edu/owl/research_and_citation/conducting_research/writing_a_literature_review.html
- The Writing Center, University of North Carolina at Chapel Hill. Literature Reviews. writingcenter.unc.edu/tips-and-tools/literature-reviews/
- APA Style (American Psychological Association). Verb Tense. apastyle.apa.org/style-grammar-guidelines/grammar/verb-tense
Written and checked by the Paperspring Editorial Team against the sources above. Found a mistake? Tell us.