An annotated bibliography is a list of sources in which each citation is followed by a short paragraph, the annotation, that summarizes the source and usually evaluates how useful it is for your research. To write one, format each citation in the style your instructor requires (APA or MLA), then write 100 to 200 words underneath it covering the source's main argument, its method or evidence, its strengths and limits, and how it fits your project. Entries go in alphabetical order, just like a reference list.
All sources in the examples are fictional.
What an annotated bibliography is for
Instructors assign annotated bibliographies early in a research project for a reason. It makes you read your sources properly, rather than collecting titles, and it shows whether you've found enough relevant, credible material before you start drafting.
It's also useful to you. When you sit down to write, you'll have a paragraph on every source reminding you what it argues and where it fits.
Descriptive vs. evaluative annotations
Annotations come in two main types, and many assignments want a mix.
| Type | What it does | Typical content |
|---|---|---|
| Descriptive (or summary) | Says what the source is about, without judging it | Main argument, scope, method, key findings |
| Evaluative (or critical) | Summarizes and also assesses the source | All of the above, plus strengths, weaknesses, credibility and relevance to your topic |
Some instructors also ask for a reflective element: how the source changed your thinking or where it will go in your paper. If the assignment just says "annotated bibliography" with no detail, an evaluative annotation is the safer choice, because it shows more of your thinking.
How to write each annotation
Work through these steps for every source.
- Write the citation first. Format it fully in the required style, so you don't have to come back to it later.
- Identify the main point. In one sentence, what is the author arguing or reporting?
- Note how they support it. Is it an experiment, a survey, interviews, an archive, a close reading of texts? How large or limited is the evidence?
- Assess it. Who is the author, and what's their expertise? Is the source current enough for your topic? Does it have obvious gaps or bias?
- Connect it to your project. Will you use it for background, as evidence for a claim, or as a view you plan to argue against?
Write the summary in your own words. If you borrow a phrase, quote it and include the page number. For help condensing a source without copying, see paraphrasing vs. summarizing.
APA format
APA 7 treats an annotated bibliography like a reference list with annotations added.
- Title the page Annotated Bibliography, centered and bold, at the top of a new page.
- Format each reference as usual: alphabetical order, double-spaced, with a 0.5-inch hanging indent.
- Start the annotation on a new line below its reference. Indent the whole annotation 0.5 inch from the left margin, in line with the hanging indent of the reference.
- Keep the annotation double-spaced. If an annotation has more than one paragraph, indent the first line of each later paragraph an additional half inch.
Okafor, C. N., & Lin, H. (2022). Sleep timing and homework completion in secondary school students. Journal of Adolescent Learning, 18(4), 211–229. https://doi.org/10.5555/jal.2022.0187
Okafor and Lin surveyed students at four secondary schools about their bedtimes and compared the answers with teacher records of homework completion over one term. Students who reported going to bed later were less likely to complete homework on time, and the gap was widest for assignments due early in the week. The authors are careful to say that their data show an association rather than a cause, and the reliance on self-reported bedtimes is a clear limitation. The study is recent and directly addresses my question about school start times, so I will use it as supporting evidence, alongside a study that measured sleep more directly.
MLA format
MLA 9 also builds on the normal works-cited format.
- Title the page Annotated Bibliography (or follow your instructor's preferred title), centered.
- Format each entry as you would on a Works Cited page: alphabetical, double-spaced, with a hanging indent.
- Place the annotation directly after the entry, indented as a block so that the citation's first line stands out. Your instructor may specify how far to indent it.
- Annotations can be written as full sentences or, if your instructor allows, as concise phrases.
Hartley, Mara J. The Quiet Coast: How Small Harbors Survived the Shipping Boom. Tidewater Press, 2021.
Hartley traces how three small fishing harbors adapted when container shipping took over their regional trade. Drawing on port records, newspaper archives and oral histories, she argues that the harbors survived by turning to tourism and boat repair rather than competing for cargo. The book's chapters move from economic history to the personal accounts of families who stayed, and a final chapter considers the environmental costs of the shift.
The second example describes the book without judging it. To make it evaluative, you would add a sentence or two on the strength of Hartley's sources and how the book fits your project.
Bibliography GeneratorFull bibliographies in any styleCommon mistakes
- Summarizing only the introduction. Read enough of the source to know its argument and evidence, not just its opening pages.
- Copying the abstract. It isn't your work and it doesn't evaluate anything.
- Writing about the topic instead of the source. Each annotation should be about this specific book or article.
- Being vague. "This source was very helpful" tells your reader nothing. Say what it helps you show.
- Inconsistent citations. Every entry should follow the same style. Check details like capitalization and italics against the citation style guide.
How many sources should you include?
Your assignment will usually give a number. If it doesn't, choose sources you would actually use in the final paper rather than padding the list. A shorter list of well-chosen, carefully annotated sources is more useful to you and more convincing to your instructor than a long list of thin entries.
Format guides for the most common sources: how to cite a journal article and how to cite a book.
Key takeaways
- Each entry is a full citation followed by a paragraph-length annotation.
- Descriptive annotations summarize; evaluative ones also judge credibility and relevance.
- APA: "Annotated Bibliography" centered and bold, annotation indented 0.5 inch under each reference.
- MLA: works-cited formatting with an indented annotation under each entry.
- Write in your own words and connect every source to your research question.
