An annotated bibliography is a list of citations where each entry is followed by a short paragraph (the “annotation”) that summarizes, evaluates, or reflects on the source. Formatting one correctly means getting two things right: the citation itself and the annotation beneath it. The exact rules depend on whether your assignment calls for APA, MLA, or Chicago style, but the overall structure is the same across all three.
Parts of Each Entry
Every entry in an annotated bibliography has two pieces. First comes the full citation, formatted exactly as it would appear on a regular Works Cited or References page. Directly beneath the citation sits the annotation, a paragraph you write yourself. The annotation typically runs three to seven sentences and does some combination of three things: summarizing the source’s main argument, evaluating its credibility or usefulness, and reflecting on how the source connects to your own research question.
How much of each you include depends on the assignment. Some instructors want all three elements in every annotation. Others ask for summary only. When in doubt, check your assignment prompt or ask your instructor which type they expect.
Descriptive vs. Evaluative Annotations
If your instructor asks for a descriptive (or “informative”) annotation, you only need to summarize. Cover the author’s main argument, the intended audience, and any key findings or conclusions. Descriptive annotations are usually two to three sentences long and contain no personal judgment about the source’s quality.
An evaluative (or “critical”) annotation goes further. You still summarize the source, but you also assess it. Is the author an established expert or a newcomer? Does the work show bias? Are there significant omissions? How does it compare with other sources on your list? Evaluative annotations typically run three to four sentences and move from a broad summary into your critique. Most college-level research assignments ask for this type because it demonstrates that you’ve actually engaged with the material rather than just skimmed it.
How to Order Your Sources
Arrange entries alphabetically by the first author’s last name, just as you would on a standard Works Cited or References page. If a source has no named author, alphabetize by the first significant word of the title (skip “A,” “An,” or “The”). Do not number the entries or group them by source type unless your instructor specifically asks you to.
Indentation and Spacing
The citation line itself uses a hanging indent, meaning the first line of the citation sits flush with the left margin and any additional lines are indented 0.5 inches. This makes the author’s last name easy to scan. Every style guide uses a hanging indent for the citation portion.
The annotation paragraph beneath the citation is indented further, but the exact measurement differs by style:
- MLA 9: Indent the entire annotation 1 inch from the left margin.
- APA 7: Indent the entire annotation 0.5 inches from the left margin (matching the hanging indent of the citation).
- Chicago/Turabian: Indent the entire annotation 0.5 inches from the left margin.
In all three styles, double-space the entire document, including the annotations. Do not add extra blank lines between entries unless your instructor tells you otherwise. Use the same font and size required for the rest of your paper (typically 12-point Times New Roman for MLA and Chicago, or 12-point Times New Roman, Calibri, or Arial for APA 7).
Formatting the Citation Line
The citation itself follows whatever style guide your class uses. Here is a simplified look at the same journal article in each format:
MLA 9: Last name, First name. “Article Title.” Journal Name, vol. number, no. number, Year, pp. pages.
APA 7: Last name, Initials. (Year). Article title. Journal Name, Volume(Issue), pages. https://doi.org/xxxxx
Chicago (notes-bibliography): Last name, First name. “Article Title.” Journal Name Volume, no. Issue (Year): pages.
The key point is that you follow the same citation rules you already use for your bibliography or reference list. The annotation is the only new element.
Writing the Annotation
Start by summarizing the source in one to two sentences. State the author’s central argument or purpose and note the type of evidence used (case studies, statistical analysis, interviews, historical review). Avoid vague language like “this article is about.” Instead, name the specific claim: “Garcia argues that bilingual education programs in elementary schools improve standardized test scores by the third year of enrollment.”
If your assignment calls for evaluation, add one to two sentences assessing the source. Consider the author’s credentials, the quality of the evidence, any noticeable bias, and how the work stacks up against other sources on your list. A useful test: would another researcher find this source credible and current?
Finally, if reflection is required, close with a sentence explaining how the source fits your project. Does it support your thesis? Offer a counterargument you need to address? Provide background context? This is where you connect the source to your specific research question.
Title Page and Heading
In MLA, center the title “Annotated Bibliography” (or a descriptive title your instructor prefers) at the top of the page, below your standard header with your name, instructor, course, and date. In APA, the annotated bibliography starts on a new page with “References” (or “Annotated Bibliography” if your instructor directs) centered and bolded at the top. In Chicago, center the title “Bibliography” or “Annotated Bibliography” at the top of a new page without bold formatting.
Quick Checklist Before Submitting
- Alphabetical order: Entries sorted by author’s last name.
- Hanging indent on citations: First line flush left, subsequent lines indented 0.5 inches.
- Annotation indent: 1 inch for MLA, 0.5 inches for APA and Chicago.
- Double spacing: Throughout the entire document.
- Consistent style: Every citation follows the same style guide, with no mixing of APA and MLA rules.
- Annotation length: Matches the assignment requirements, typically 100 to 200 words per entry.
- Annotation type: Descriptive, evaluative, or both, depending on what your instructor asked for.