A competently written paragraph is a sentence or group of sentences that conveys a single idea either expressed by a topic sentence or implied by the information presented. That information may define, qualify, explain, illustrate, expand, or support the main idea, which is itself and aspect of the purpose of the whole paper. The relationships between the sentences are clear; the second sentence follows from the first, the third from the second, and so on. Each sentence serves the main idea of the paragraph.
The paper quoted in the "Whole Paper" section advances through several points of contrast between "civil disobedience" and "dissent" in a clear and logical fashion because each paragraph elaborates a different aspect of the subject with definitions and examples. The following paragraph begins with a topic sentence that introduces contrasting ideas, but fails to develop that contrast.
(1) There are two basic types of ideological critics of television entertainment: those that complain about television's constant reinforcement of middle-American values, and those who criticize television's occasional portrayal of less than conventional values. (2) The first group of critics have a strong but difficult case to prove. (3) Television is at its strongest level of persuasion when it is affirming the biases of its audience. (4) How do you convince people that they have had injustices done to them when television is constantly reaffirming and telling them that they're right? (5) Feminists, rightists, leftists, environmentalists and other activists that advocate a different lifestyle are seldom successful in their efforts to lessen the constant reinforcement of the status quo.
This paragraph begins well enough, identifying and characterizing two types of critics. But the third sentence does not connect well with the first two: we need to know what the assertion that TV is at its most persuasive when affirming the biases of its audience has to do with the "difficult case" that the first kind of ideological critic must prove. The fourth sentence must relate in some manner to the second type of critic, but how? And what do feminists, rightists,leftists, and environmentalists of sentence five have to do with two kinds of critics mentioned in sentence one? The reader leaves the paragraph unsure of its main idea, in part because of the writer's use of jargon.
In the following paragraph from a paper that compares the invertebrate populations in three intertidal zones off Long Island, the ideas are clearly expressed. The relationships between those ideas, however are unclear; indeed, the last three sentences appear to be introducing completely new ideas rather than representing those ideas as aspects of the main idea.
The ocean beach provided the problem of turbulence both in the movement of water and sand. Adaptations to this were shown by the large number of shelled, burrowing organisms present. The exception to this was the seanettle which usually stayed out past the breaking waves, but occasionally was caught by the breakers and brought in near shore. The starfish combined a heavy, horny covering with the ability to regenerate lost arms in order to survive the heavy surf. Desiccation is a problem on the ocean beach, but most organisms adapt by either burrowing until the tides return or by moving out with the tide.
The main idea - that the researchers found life forms adapted to the turbulent environment - is stated, but the ideas that help us understand in what ways organisms have adapted to specific conditions seem to be presented at random. The paragraph suffers from a lack of both development and coherence. In addition, the pronoun this in sentences two and three has no clear antecedent, and presents, instead of continuity, only a kind of awkwardness. Rewritten with a regard to connecting the assertions, the paragraph might become:
The ocean beach was the site of turbulence in both water and sand. Organisms that have adapted to this environment often burrow, or move in and out with the tide to prevent desiccation. Others have developed shells for protection. With its hard, horny covering and its ability to regenerate lost arms, the starfish survives the heavy surf. Most of the organisms present had adapted to turbulent conditions. Occasionally one would appear, such as the seanettle that usually stays out past the breakers, but had been caught and brought in near shore by the large waves.
EVALUATING THE PARAGRAPH
Is the main idea sufficiently limited to need no more than one paragraph to convey?
Is the main idea expressed in a single topic sentence, or can on one be inferred from the paragraph?
Does the paragraph contain sufficient support for the main idea? Support can define, extend, qualify, explain, or illustrate the main idea, and it may take the form of definition of terms, facts, statistics, anecdotes, quotations, and so on.
Do all the supporting assertions relate to the main idea (unity)?
Are the supporting details arranged in the most effective order (development)? Is the topic sentence positioned in the paragraph to introduce the main idea at the best time?
Do the sentences follow one from the other (coherence)? Are the relationships among them apparent?