One way to evaluate your sources is to write an annotated bibliography as shown below. An annotation is a short explanatory note about the contents of a source, also called a précis.
A précis differs from a summary by its brevity and polished style. It requires you to capture in just a few words the ideas of an entire article, chapter, or a book. Use it when you are concerned with facts, the what of the matter. You serve as the bridge between another author and your reader, so you must condense fairly and without bias. Usually, information condensed into a précis has more value than a summary, so it deserves a polished style for transfer later to the first draft.
Success with each annotation for your bibliography or précis requires the following:
Condense the original with precision and directness. Reduce several paragraphs into a sentence, tighten an article into a brief paragraph, and summarize a book into a page.
Preserve the tone of the original. If the original is serious, suggest that tone in the précis. In the same way, retain moods of doubt, skepticism, optimism, and so forth.
Limit your quotation of the original by writing the précis in your own language. However, retain exceptional phrases from the original, enclosing them in quotation marks.
Provide documentation locating the source of your material.
Sample annotation from source summary sheet:
"In a section called "Apathy Toward Communication Skills," Powell states that television tends to speak in choppy, simplistic, and superficial language in order to appeal to the widest possible audience. He fears that children will lose the ability to express verbally deep thoughts or feelings."
In only a few words, the writer has abridged the essential elements of a long section of a chapter. Since an annotation clarifies the nature of a work, it seldom extends beyond one paragraph. Note below how the writer used the précis for his bibliography:
"Television can invigorate the vocabulary of children, although some critics argue otherwise. Jon Powell, for example, states that television tends to speak in choppy, simplistic, and superficial language in order to appeal to the widest possible audience (41-47), and he cites numerous examples. In general, he fears that children will lose the ability to expess verbally deep thoughts or feelings."
(Generally, a précis will not include page numbers. However, if you focus on a specific section in a major work, it may be helpful to indicate the page.)