To write an annotated bibliography, list each source as a full citation in your required style, then add a short paragraph that summarizes, evaluates and explains how the source fits your research.
This guide covers the three types of annotation, how long they should be, a step-by-step process, worked examples, and the layout rules for APA 7, MLA 9 and Chicago.
The Four Moves of a Strong Annotation
A strong annotation does four things in about 150 to 200 words: it states the source's main argument or finding, notes the method or evidence, judges its reliability and limits, and explains how it will help your project.
Each entry starts with a correctly formatted citation, and the entries are ordered exactly as your style orders its reference list.
What Is an Annotated Bibliography?
An annotated bibliography is a list of sources in which each citation is followed by a brief paragraph about that source. The paragraph is the annotation.
Tutors set it for several reasons. It proves you have read the sources rather than skimmed abstracts, it makes you judge quality early, and it becomes the raw material for a literature review or research paper later.
Annotated Bibliography or Literature Review?
The two are often confused. An annotated bibliography treats each source separately, one entry at a time. A literature review synthesizes sources by theme, comparing and connecting them in continuous prose.
| Feature | Annotated bibliography | Literature review |
|---|---|---|
| Unit of writing | One paragraph per source | Themes that draw on many sources |
| Order | Alphabetical or as your style requires | Logical, by theme or argument |
| Purpose | Summarize and assess each source | Map the field and identify a gap |
| Typical stage | Early in a project | Later, before or within the paper |
Types of Annotation
Your brief usually tells you which type to write. If it only says "annotate", a combined annotation is the safest choice.
| Type | What it does | Typical use |
|---|---|---|
| Descriptive (informative) | Summarizes the content, scope and main points without judging them | Introductory courses and source lists |
| Evaluative (critical) | Assesses strengths, weaknesses, bias and methodological quality | Upper-level and graduate work |
| Combined | Summarizes briefly, then evaluates and explains relevance | Most research projects and theses |
Some tutors also ask for a reflective sentence on how the source changed your thinking. Add it only if the brief asks for it.
How Long Should an Annotation Be?
Most annotations run from about 100 to 300 words. Undergraduate briefs often expect around 150 to 200 words; graduate work may expect more detail on method and limitations.
Length should follow purpose. A descriptive annotation can be shorter, while an evaluative one needs room to justify its judgment. If your brief gives a word count, treat it as firm.
Making Every Word Count
Skip phrases such as "This article discusses" or "In this book, the author argues". Open with the author's name and a strong verb instead: "Harlow argues", "Ortega and Byrne compare". The saving across ten entries can be a full annotation's worth of words.
Avoid restating the title or the publication details, since they already appear in the citation. Spend the space on findings, method and your judgment.
How to Write an Annotated Bibliography Step by Step
- Define your research question. It tells you which sources belong and what to say about relevance.
- Find and select sources. Choose scholarly, recent and relevant work, and note why each one earned a place.
- Read actively. Record the argument, method, sample, key findings and limitations as you go.
- Write the citation. Format it in your required style before writing the annotation, so details are not lost.
- Draft the annotation. Summarize, evaluate, then link the source to your project.
- Order the entries. Alphabetize by first author for APA, MLA and Chicago, unless your tutor asks for themes.
- Edit for consistency. Keep tense, length and level of detail similar across entries.
For the citations themselves, the free Bibloq citation generator fills in details from a DOI, ISBN or URL, which leaves you more time for the annotations.
How to Write a Descriptive Annotation
A descriptive annotation answers "what is this source about?". Keep it neutral, specific and short.
- State the author's purpose or research question.
- Name the type of source: study, review, book, report or policy.
- Summarize the main points or findings in your own words.
- Note the scope, such as the population, period or setting covered.
Descriptive example (APA 7).
Ortega, L., & Byrne, S. (2021). Peer review in first-year writing courses. Journal of Writing Pedagogy, 14(2), 55–71. https://doi.org/10.0000/jwp.2021.0142
Ortega and Byrne report a semester-long study of peer review in four first-year writing classes at one university. Students exchanged drafts twice, using a structured feedback form. The authors compare revision quality between students who received form-guided feedback and those who exchanged open comments, and describe how students used each type of feedback in their final drafts.
The citation above is illustrative; it shows layout rather than a real article.
How to Write an Evaluative Annotation
An evaluative annotation adds judgment. It tells the reader how far the source can be trusted and how useful it is.
- Authority: what qualifies the authors or publisher to speak on the topic?
- Method: is the design suited to the question, and is the sample adequate?
- Currency: is the source recent enough for your field?
- Limits and bias: what does the source not cover, and who funded it?
- Relevance: which part of your project will it support?
Evaluative continuation of the same entry. The structured form produced more specific comments, but the study took place at a single institution with a small sample, so its findings may not transfer to other settings. The authors also rely on instructor ratings of revision quality, which introduces possible bias. Even so, the feedback form is described in enough detail to replicate, and the study supports my argument that guided peer review is worth testing in larger classes.
Annotated Bibliography Layout in APA 7, MLA 9 and Chicago
Each style keeps its usual reference format and adds the annotation directly after each entry. Check your tutor's template, since layout details vary between courses.
| Style | Page title | Entry format | Annotation placement |
|---|---|---|---|
| APA 7 | Annotated Bibliography, bold and centered | Standard APA reference, double spaced, 0.5-inch hanging indent | New paragraph below the reference, indented 0.5 inch from the left margin |
| MLA 9 | Annotated Bibliography (or Works Cited) centered | Standard Works Cited entry with hanging indent | Directly below the entry, usually as an indented block |
| Chicago | Annotated Bibliography, centered | Bibliography entry with hanging indent | New indented paragraph after the entry |
An MLA 9 Entry with Annotation
Harlow, Ruth. Reading the Modern City. Northgate UP, 2020.
Harlow traces how novelists from the 1890s to the 1930s used the city street to stage questions of class and anonymity. Her close readings are persuasive, though the focus on British writers limits the comparison I need with American fiction.
In both APA and MLA, keep the whole page double spaced, and keep entries in alphabetical order by the first element of each citation.
Common Annotated Bibliography Mistakes
| Mistake | Fix |
|---|---|
| Copying the abstract | Summarize in your own words and add your own evaluation |
| Summary with no judgment | Add at least two sentences on reliability and relevance, unless the brief asks for descriptive only |
| Inconsistent citation format | Format every entry in one style and edition |
| Annotations of wildly different lengths | Keep each within the same word range |
| Weak or irrelevant sources | Replace them with scholarly sources that answer your question |
How Bibloq Helps with Annotated Bibliographies
Send your research question, the number and type of sources required, the annotation type, word count per entry and citation style. A writer in your subject prepares a custom annotated bibliography with correctly formatted entries and focused annotations, for study and reference.
You can also send your own draft for editing, and an editor will check citation accuracy, consistency and the balance of summary and evaluation. Free revisions within the scope of your original request are included.
Want a Custom Annotated Bibliography to Learn From?
Send your topic, the number of sources, the annotation type and your style. You get correctly formatted entries with focused, evaluative annotations.
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Frequently Asked Questions
Follow your brief. Short assignments often ask for five to ten sources; research projects and theses may need twenty or more.
It depends on your tutor. Descriptive annotations are usually written in the third person, while some briefs allow "I" when you explain how a source helps your research.
In APA, MLA and Chicago, yes, by the first element of each citation, usually the first author's surname. Some tutors ask for thematic grouping instead.
Usually not. Annotations are normally written as full paragraphs unless your tutor provides a bulleted template.
In APA 7 and MLA 9 the whole page, including annotations, is double spaced. Chicago papers vary, so check your course guidance.
A summary reports what the source says. An evaluation judges how reliable, relevant and useful it is for your question.
Not for the source being annotated, since its citation is directly above. If you mention a different source inside an annotation, cite it in your style.
Many fields prefer work from the last five to ten years, while history and literature often rely on older sources. Your brief or tutor sets the standard.