Writing an Annotated Bibliography: Specific Information About Sources

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An instructor may ask you to create an annotated bibliography as part of the research process before you have even written your first draft; however, writing an annotated bibliography may also be a component of your completed research project. This type of bibliography goes beyond simply giving citation information and provides very specific information about sources you either consulted to write your paper or intend to consult (when it is an assignment due as part of the research process).

The purpose of writing an annotated bibliography

Writing an annotated bibliography is focused on explaining the content of your sources, assessing them and sharing the information with readers who might be less knowledgeable on the topic. A well-written annotated bibliography accomplishes several things:

  • You to use critical thinking while evaluating the content of your sources, how they fit into the general area of research and how they correspond to your thoughts, ideas or primary research (when applicable)
  • Demonstrates that you have not only read, but also understand the material in your sources
  • Shows you are a competent researcher
  • Provides a way for readers to review background information and work in the area of study to determine if the topic interests them

What to include when writing an annotated bibliography

There are four main elements to consider when writing an annotated bibliography:

  1. A bibliography presentation that follows a specific official style guide – consult your instructor for the format you must follow
  2. The key points or purpose of a source (its thesis)—demonstrates that you have read and understand the material
  3. Examines the authority or qualifications of the author of each source
  4. Discussion on how effective and useful the source is for the general topic with respect to research and how it ties into your own research assignment

In addition to these four elements, there are two additional elements that include more analysis that may be required by your instructor:

  1. An evaluation of the point of view of a source and whether there is bias or the aim is toward a more specific audience
  2. Links to related work or studies on the same topic though establish connections between the sources used in your annotated bibliography.

Choosing the annotation style for an annotated bibliography

While an instructor may specify which style of annotation you should use for an annotated bibliography, sometimes the style is left to your discretion and is based on the nature and scope of your research paper project. There are three main types of annotation used when writing an annotated bibliography:


This style of annotation describes the source without including information about any research arguments, hypotheses or messages within the source. It is similar to the more commonly used research paper abstract in that it does not include an evaluation or critique of the source. It basically answers the following question. Does the source focus on the topic you are researching?


This style of annotation is also considered critical or analytical. This is the most common annotation style, and it incorporates an evaluation and critique of sources. Areas of focus include a source’s strengths and weaknesses and whether the source applies to your research conclusions. It determines whether the reasoning and methodology in the source is sound and determines whether the source focuses on the issues important to your topic. Determining how a particular source compares to other sources you are evaluating is also part of this annotation style.


This style of annotation is essentially a summary of the content, message and argument within a source. It includes the hypothesis, methods and findings of a particular source, but it does not include a critique or evaluation. The original author’s main arguments and conclusions are a focal point of this style of annotation.

Different writing styles for writing an annotated bibliography

Once you have chosen an annotation style to determine the content, you must also decide on a writing style. There are two types of writing styles when it comes to writing an annotated bibliography:


Writing an annotated bibliography with a telescopic style is the more difficult of the two. This style is extremely concise and focuses on providing minimal, yet complete information and sentence structure that maintain clarity. Unless you are required by an instructor to use this style, you might want to use the second writing style.


If you are required to use the paragraph writing style (most common) when writing an annotated bibliography, do not be shy about writing a full, in-depth paragraph (or two) for each source. The nature of this style demands a full discussion and evaluation of each source.

Format of an annotated bibliography

When writing an annotated bibliography, the specific format is dictated by the official style guide you are required to follow. If you are not sure, consult your instructor before formatting.

How the annotated bibliography is arranged (alphabetically, chronologically or by publication date) is likely defined by your instructor as well. However, the overall format of the content is typically the same and follows the below general format:

  • An introduction to the annotated bibliography that incorporates why you selected particular sources, which were not used in your final research paper and why they were not used

For each source:

  • A citation that shows all the bibliographic information that adheres to the documentation style of the official guide you are required to follow
  • An annotation of the source following the annotation style you selected

The length of each annotation varies, but generally, most are between 100-300 words in length. Several factors determine the length of each entry when you are writing an annotated bibliography. First, the annotation style dictates how much information is included. If you are writing a simple summary, the annotation is much shorter than if you are using an in-depth analysis. Ask your instructor on the specific length required for each source if you are not sure.