Quick answer: how to write an annotated bibliography
An annotated bibliography is a list of sources in which each citation is followed by a short paragraph, called an annotation. The annotation sums up the source, judges it, and says how it helps your project.
- Read the assignment: which citation style, how many sources, what each annotation must cover.
- Find and choose your sources.
- Read each source and take notes on its main claim, method and evidence.
- Write the full citation in the required style.
- Under it, write the annotation: summary, then evaluation, then reflection.
- Put the entries in alphabetical order and format the page.
Most annotations are one paragraph of about 100 to 200 words. The citation follows the normal rules of your style. The annotation starts on a new line and is indented.
What an annotated bibliography is
Every entry has two parts:
- The citation. The same reference you would put in a reference list or a Works Cited page.
- The annotation. Your own short note about the source, written as a paragraph.
Instructors set this assignment for two reasons. It shows that you have read your sources and not only collected them. It also makes you decide, early on, which sources are worth using and what each one will do in your paper.
| Do not confuse it with | Difference |
|---|---|
| A bibliography or reference list | Lists the citations only, with no notes. |
| An abstract | Only describes the work, and is usually written by its author. An annotation is written by you. |
| A literature review | An essay that discusses the sources together, by theme. An annotated bibliography takes them one at a time. |
How to write an annotated bibliography in six steps
- Read the assignment. Look for the citation style, the number of sources, the kind of sources allowed, the length of each annotation, and whether it should be summary only or summary plus evaluation. If the instructions do not say, ask.
- Find and choose your sources. Search your library databases. Read the abstract or introduction of each result and keep only the ones that speak to your topic or research question.
- Read and take notes. For each source, write down the main claim, how the author supports it, who the author is, and what you might use it for. Take the notes in your own words. Notes copied from the source tend to end up in the annotation.
- Write the citation. Use the full reference format of your style. The citation generator can format it for you in APA, MLA or Chicago.
- Write the annotation. Start on a new line under the citation. Cover the summary, the evaluation and the reflection, in that order. The next section shows what each part needs.
- Order and format. Put the entries in alphabetical order by the first word of each citation, usually the author’s last name. Then apply the indents and spacing for your style.
What goes in an annotation
A full annotation does three jobs. The Purdue OWL guide to annotated bibliographies calls them summarize, assess and reflect.
| Part | Questions it answers | How it can start |
|---|---|---|
| Summary | What is the source about? What is the main claim? How did the author reach it? | “The author argues that…”, “This study examines…” |
| Evaluation | Is the author qualified? Is the evidence strong? Is the source current? Is there bias, or something missing? | “The evidence is strong because…”, “A limit of the study is…” |
| Reflection | How does it help your project? Does it support, challenge or add background to your argument? | “I will use this source to…”, “This challenges my claim that…” |
Not every assignment wants all three. There are two common types:
- Descriptive annotation. Summary only. Also called an informative annotation.
- Evaluative annotation. Summary plus evaluation, and often reflection. Also called a critical annotation.
Whichever type you write, keep to these rules:
- Write in your own words. Do not copy the abstract.
- Write full sentences in one paragraph, not bullet points, unless your instructor says otherwise.
- Name specifics: the method, the sample, the main finding. “This article is useful” says nothing.
- Leave out small details and long quotations.
How long an annotation should be
Follow the assignment first. If it gives no length, write one paragraph of about 100 to 200 words, which is roughly four to eight sentences. That gives you room for all three parts.
| Type | Usual length |
|---|---|
| Summary only | 2 to 4 sentences |
| Summary, evaluation and reflection | One paragraph, about 100 to 200 words |
| Detailed analysis for a thesis or long project | More than one paragraph, if your instructor asks for it |
None of the three style guides sets a word count. Purdue OWL notes that annotations can run from a couple of sentences to a couple of pages, depending on the purpose.
APA, MLA and Chicago format compared
The citation follows the normal rules of each style. The differences are in the indent of the annotation, the spacing and the title of the page.
| Feature | APA 7 | MLA 9 | Chicago 17 |
|---|---|---|---|
| Citation | Reference list format, hanging indent of 0.5 inch | Works Cited format, hanging indent of 0.5 inch | Bibliography format, hanging indent of 0.5 inch |
| Annotation starts | On a new line under the citation | On a new line under the citation | On a new line under the citation |
| Annotation indent | Whole annotation 0.5 inch from the left margin, like a block quotation. First line not indented further. | Whole annotation 1 inch from the left margin | Whole annotation 0.5 inch from the left margin |
| Spacing | Double throughout | Double throughout | Often single within an entry, with a blank line between entries. Check with your instructor. |
| Order | Alphabetical | Alphabetical is usual. By date or by subject is also allowed. | Alphabetical |
| Page title | Usually “Annotated Bibliography” | “Annotated Bibliography” or “Annotated List of Works Cited” | Usually “Annotated Bibliography” |
In APA, if an annotation has more than one paragraph, indent the first line of the second and later paragraphs by another 0.5 inch. APA also says to follow your instructor’s requirements for what the annotations contain. MLA lets you write annotations as short phrases or as full sentences, as the MLA Style Center explains. The indent sizes above are the ones listed with the Purdue OWL annotated bibliography samples.
In Google Docs, set the hanging indent on the citation with Format > Align & indent > Indentation options > Special indent > Hanging. For the annotation, open the same window and type 0.5 (or 1 for MLA) in the Left box, with Special indent set to None. Our guides to APA format in Google Docs and MLA format in Google Docs cover the rest of the page setup.
APA 7 annotated bibliography example
The sources in all three examples are invented, so do not cite them. Each annotation is labeled in the notes underneath so you can see the three parts.
Rivera, J. A. (2022). Sleep and the student brain: How rest shapes learning. Example University Press.
Rivera reviews two decades of research on sleep and memory in college students. The book argues that regular sleep of seven hours or more does more for exam results than extra study time late at night. Rivera is a sleep researcher, and each chapter draws on published studies, which makes the book a reliable overview. Most of the studies come from large universities in the United States, so the findings may not apply to part-time or older students. I will use chapter 3 to support my claim that all-night study sessions lower test scores, and the reference list to find original studies.
- Summary: sentences 1 and 2.
- Evaluation: sentences 3 and 4.
- Reflection: sentence 5.
Format: the citation has a hanging indent. The whole annotation sits 0.5 inch from the left margin, and its first line is not indented any further. Everything is double spaced in a real paper. Build the citation with the APA citation generator.
MLA 9 annotated bibliography example
Okafor, Nia. Screens in the Seminar Room: Attention and Note-Taking in College Classes. Example University Press, 2021.
Okafor compares students who take notes by hand with students who type them on laptops in twelve first-year seminars. She finds that the laptop users wrote down more words but remembered fewer of the main ideas a week later. The study is carefully designed, and Okafor explains her methods in enough detail to repeat them. Its weak point is size: all twelve seminars were at one college. This book gives my essay its central example of how a tool can change what students learn, and I will set it against sources that defend laptops in class.
- Summary: sentences 1 and 2.
- Evaluation: sentences 3 and 4.
- Reflection: sentence 5.
Format: the citation has a 0.5 inch hanging indent. The annotation is indented 1 inch from the left margin, so it stands apart from the citation. Everything is double spaced in a real paper. Build the citation with the MLA citation generator.
Chicago annotated bibliography example
This example uses the bibliography format of Chicago’s notes and bibliography system, 17th edition.
Lindqvist, Maren. Mill Town Rivers: Water and Work in the Industrial City. Boston: Example University Press, 2019.
Lindqvist traces how three river towns changed between 1850 and 1920 as textile mills took control of the water supply. She argues that fights over water, more than wages, drove the first local labor movements. The book rests on town records and mill company letters, which Lindqvist quotes at length, so the claims are easy to check. It says little about the workers’ own accounts, which leaves the story one-sided in places. I will use it for background on mill ownership and compare its argument with oral histories from the same towns.
- Summary: sentences 1 and 2.
- Evaluation: sentences 3 and 4.
- Reflection: sentence 5.
Format: the citation has a hanging indent and the annotation starts on a new line, indented 0.5 inch. The 18th edition of Chicago, published in 2024, no longer requires the place of publication, so check which edition your course follows. Build the citation with the Chicago citation generator.
Common mistakes to avoid
- Copying the abstract. This is plagiarism, even with a few words changed. Close the source and write from your notes. See how to paraphrase without plagiarizing.
- Summary only, when evaluation was asked for. Check that each annotation has all the parts the assignment lists.
- Vague praise. Replace “a good, useful source” with what it is good for and why.
- Annotating before reading. An annotation based on the title and abstract is easy to spot. Read at least the introduction, the conclusion and the sections you plan to use.
- Mixing styles. Use one citation style for every entry.
- Wrong indents. The citation gets a hanging indent. The annotation gets a block indent.