An annotated bibliography is a list of sources (books, articles, websites) where each citation is followed by a short paragraph, usually 3 to 7 sentences, that summarizes the source, evaluates its quality, and explains how it relates to your research. It looks like a regular Works Cited or References page, but with a brief write-up beneath each entry. Below you’ll find the anatomy of a good annotation, full examples in multiple citation styles, and the differences between the two main types your instructor might assign.
The Three Parts of an Annotation
A complete annotation does three things in sequence: summarize, assess, and reflect. Not every assignment requires all three, but understanding each part helps you write stronger entries regardless of the format your instructor wants.
Summarize. In one to three sentences, describe the source’s main argument, scope, or findings. Think of it as answering: “If someone asked what this article is about, what would you say?”
Assess. Evaluate the source’s reliability, potential bias, and usefulness compared with other sources on your topic. Is the author a recognized expert? Is the data current? Does the publication have a particular slant?
Reflect. Explain how the source fits into your own research. Did it change your thinking? Does it support or challenge your thesis? Will you use it as background context or as a central piece of evidence?
When your instructor asks for a “complete” or “analytical” annotation, they typically want all three moves. When they ask for a “summary” annotation, the first move alone may be enough.
Full Annotated Bibliography Example (MLA)
Here is a sample MLA entry with all three parts labeled so you can see how the pieces connect. In MLA format, the citation uses a hanging indent (the first line is flush left, subsequent lines are indented 0.5 inches), and the annotation paragraph beneath it is indented 1 inch from the left margin.
Ehrenreich, Barbara. Nickel and Dimed: On (Not) Getting By in America. Metropolitan Books, 2001.
Ehrenreich recounts her experience working minimum-wage jobs across the United States to test whether low-wage workers can actually survive on their earnings. She finds that even with constant employment, housing costs, transportation, and basic necessities push workers into a cycle of debt and instability. [Summary] The book is based on firsthand experience rather than statistical analysis, which makes it vivid but limits its generalizability. Ehrenreich is transparent about her advantages as a white, educated woman, though critics have noted she sometimes overlooks the coping strategies long-term low-wage workers develop on their own. [Assessment] This source will anchor my paper’s argument that the federal minimum wage has not kept pace with the cost of living, providing concrete, narrative evidence to pair with the Bureau of Labor Statistics data I plan to cite. [Reflection]
In your actual paper, you would not include the bracketed labels. They are here only to show you where each part begins.
Full Annotated Bibliography Example (APA)
APA 7th edition uses a different citation format, and the annotation is indented 0.5 inches rather than 1 inch. The citation itself still has a hanging indent so the author’s last name sits flush left.
Dweck, C. S. (2006). Mindset: The new psychology of success. Random House.
Dweck presents her research on two belief systems she calls “fixed mindset” and “growth mindset,” arguing that people who believe abilities can be developed through effort outperform those who see talent as innate. She draws on studies of students, athletes, and corporate leaders to support her framework. The book is well cited and widely referenced in education research, though some scholars have raised concerns about the replicability of specific growth-mindset interventions in classroom settings. For my project on student motivation in online courses, Dweck’s framework provides the theoretical lens I will use to interpret survey results on how students respond to academic setbacks.
Full Annotated Bibliography Example (Chicago)
Chicago style annotations also use a 0.5-inch indent beneath a hanging-indent citation. The citation format itself differs from both MLA and APA, using a footnote-style author-date or notes-bibliography system depending on your discipline.
Klinenberg, Eric. Palaces for the People: How Social Infrastructure Can Help Fight Inequality, Polarization, and the Decline of Civic Life. New York: Crown, 2018.
Klinenberg argues that shared physical spaces like libraries, parks, and community centers serve as “social infrastructure” that strengthens neighborhood bonds and reduces isolation. He combines sociological research with case studies from cities that invested in public spaces after natural disasters. The evidence is compelling, though the book focuses heavily on urban environments and says little about rural communities facing similar challenges. This source directly supports my thesis that public library funding is a cost-effective strategy for increasing civic engagement, and I will draw on Klinenberg’s data in my policy-recommendation section.
Descriptive vs. Evaluative Annotations
Instructors typically assign one of two types, and mixing them up is a common reason students lose points.
Descriptive annotations (sometimes called “informative” annotations) only summarize. In two to three sentences, you describe the source’s main purpose, intended audience, and conclusions. You do not offer your opinion on whether the source is good, bad, or biased. Think of it as a neutral snapshot. For example:
This article examines the effects of social media use on sleep quality among college students aged 18 to 24. The authors surveyed 1,200 undergraduates and found a strong correlation between screen time after 10 p.m. and reduced sleep duration. The study was published in the Journal of Adolescent Health and is intended for researchers in public health and psychology.
Evaluative annotations (sometimes called “critical” annotations) go further. In three to four sentences, you still summarize, but you also judge the source’s strengths, weaknesses, bias, and contribution to the broader literature on your topic. You might note that the author’s small sample size limits the findings, or that the research fills a gap other scholars have overlooked. For example:
This article examines the effects of social media use on sleep quality among college students aged 18 to 24, surveying 1,200 undergraduates and finding a strong correlation between late-night screen time and reduced sleep duration. The large sample size and rigorous methodology make it one of the more reliable studies on this topic. However, the authors rely entirely on self-reported data, which may understate actual screen time. This study will serve as the primary empirical source for my argument that universities should promote digital wellness programs.
If your assignment sheet does not specify a type, evaluative annotations are generally the safer choice because they demonstrate deeper engagement with the material.
How Long Should Each Annotation Be?
Most annotations run between 100 and 200 words, roughly one substantial paragraph. Some instructors set a specific word count or sentence count per entry, so check your assignment guidelines first. A descriptive annotation can be as short as two to three sentences. An evaluative annotation that includes summary, assessment, and reflection usually lands closer to five to seven sentences.
The full bibliography itself might contain anywhere from 5 to 20 sources depending on the scope of your project. An annotated bibliography for a short research paper might list 5 to 8 sources, while one for a thesis or capstone project could include 15 or more.
Formatting Basics Across All Styles
- Hanging indent on the citation: The author’s last name sits flush left. Every subsequent line of the citation is indented 0.5 inches. This rule is the same in MLA, APA, and Chicago.
- Annotation indent: MLA 9th edition requires the annotation paragraph to be indented 1 inch from the left margin. APA and Chicago both require a 0.5-inch indent for the annotation.
- Alphabetical order: Entries are listed alphabetically by the first author’s last name, just like a standard Works Cited or References page.
- Spacing: Double-space the entire document in MLA and APA. Chicago may be single-spaced within annotations depending on your instructor’s preference.
- Title: Center the title “Annotated Bibliography” at the top of the page. In APA, use bold for the title. In MLA, no bold or underline is needed.
Getting the citation format right matters just as much as the annotation itself. Use your style guide’s rules for author names, publication dates, italics, and punctuation. If you format the citation in MLA but write the annotation in a generic style, you’ll still lose points for inconsistency.