How to Write an Annotated Bibliography

An annotated bibliography is a reference list where each entry includes a short paragraph (the annotation) describing and evaluating the source. It's a common assignment in undergraduate and graduate courses, and it's also a useful tool for organizing your sources before writing a paper.

What Goes in an Annotation?

Each annotation typically answers three questions in 150--200 words:

1. What does the source say? Summarize the main argument or findings.
2. How is it useful? Explain how this source relates to your research topic.
3. Is it credible? Briefly evaluate the source's reliability, methodology, or bias.

Types of Annotated Bibliographies

Descriptive (Summary)

Summarizes the source without evaluation. Just describes what the author says.

Evaluative (Critical)

Summarizes and assesses the source's strengths, weaknesses, and relevance.

Combination

Most assignments expect both summary and evaluation. When in doubt, include both.

APA Format Example

Smith, J. D., & Johnson, M. K. (2025). The impact of citation accuracy on academic publishing. Journal of Academic Writing, 15(3), 45--62. https://doi.org/10.1234/example

Smith and Johnson examine citation error rates across 500 published journal articles in the social sciences. Using a systematic review methodology, they found that 23% of citations contained at least one formatting error, with missing DOIs and incorrect author name formatting being the most common issues. The study is relevant to my research on academic writing standards because it provides quantitative evidence that citation errors remain widespread even in peer-reviewed work. The large sample size and rigorous methodology strengthen the findings, though the study is limited to social science journals and may not generalize to other disciplines.

APA Formatting Notes

• Standard APA reference entry first
• Annotation starts on a new line, indented 0.5 inches (same as hanging indent)
• No additional heading or label
• Double-spaced throughout

MLA Format Example

Smith, John D., and Mary K. Johnson. "The Impact of Citation Accuracy on Academic Publishing." Journal of Academic Writing, vol. 15, no. 3, 2025, pp. 45--62.

This study reviews citation accuracy across 500 social science journal articles, finding that nearly one-quarter contain formatting errors. The most common issues identified are missing DOIs and incorrectly formatted author names. The research supports my argument that automated citation tools can significantly improve academic writing quality. Smith and Johnson's systematic approach and large sample make the findings compelling, though the focus on social sciences limits broader applicability.

MLA Formatting Notes

• Standard MLA Works Cited entry first
• Annotation starts on the next line, indented 0.5 inches
• Double-spaced throughout
• Typically shorter than APA annotations (100--150 words)

Step-by-Step Writing Process

1. Find and read your sources. You can't annotate what you haven't read.
2. Create the citation. Format the reference in your required style. Use CiteTools.io to generate it from a DOI or URL.
3. Write a 2--3 sentence summary. What is the source about? What are the main findings or arguments?
4. Add 1--2 sentences of evaluation. Is the methodology sound? Is the author credible? Are there limitations?
5. Connect it to your research. How does this source support or challenge your thesis? Why is it relevant?
6. Keep it concise. 150--200 words per annotation. Cut anything that doesn't serve the three questions above.

Common Mistakes

1. Writing too much summary, not enough evaluation. The annotation isn't a book report -- assess the source.
2. Using first person excessively. "I think this source is useful" can become "This source contributes to the field by..."
3. Copying the abstract. Annotations must be in your own words. See our guide on paraphrasing correctly.
4. Inconsistent citation formatting. Every entry must use the same style. Check our Harvard guide if that's your required style.
5. Annotating sources you haven't read. Professors can tell.

Try It with CiteTools

The hardest part of an annotated bibliography is the writing, not the formatting. Let CiteTools.io handle the citation formatting -- paste any DOI, URL, or ISBN and get a perfect reference entry. Then focus your energy on writing strong annotations.