To compare things, people, places, qualities, or ideas is to identify the ways they are similar or the ways they are both similar and different. To contrast things is to show only how they are different. Comparisons and contrasts are both drawn between elements in the same general class, however.
She compared prices at three different stores before buying. Her style of shopping contrasted sharply with her husband's.
In writing about similarities, use compare to.
James Watson and Francis Crick compared the molecular structure of DNA to a zipper.
In writing about similarities and differences, use compare with.
We compared the features of the new computer with those of the old one.
comparison and contrast as a method of development
Comparison and contrast is a method of development for presenting similarities and differences between two or more things. Comparison and contrast can be used separately or together.
First, decide on your basis of comparison. Suppose, for example, that you are going to compare and contrast movies of the 1950s and movies of the 1990s. After reviewing many movies of both decades, you note several elements that you might consider for setting up your bases of comparison: types of plots (both content and development), methods of acting, quality of dialogue or screenwriting, amount of violence shown (if any), and quality and function of accompanying music. You further determine that some features are irrelevant and should not be included in your comparisons: models of cars appearing in the movies, styles of houses, celebrity status of the stars at the time, or size of the casts. Finally, you review all your bases of comparison and limit them to an appropriate number, depending on the length of your writing project.
After you have chosen your bases of comparison, you must select a method oi presentation. You might wish to discuss all the elements of one thing and then all the elements of the second thing, a structure called the whole-by-whole method. Or you might wish to compare or contrast the elements of both things one by one, a method called the point-by-point method. The following discussion by a college undergraduate is organized according to the whole-by-whole method, describing one type of animal and all its relevant characteristics before going on to describe the other type, its prey, in the same manner.
The big cats of Africa have, like all cats, developed a set of adaptations that allow them to chase down their prey. Besides the forward-oriented eyes and sharp tearing and shearing teeth that are universal in mammalian carnivores, felines have exceedingly flexible backbones and strong shoulder musculature. With this kind of physique, a running cat can reach forward with its fore paws, pull itself rapidly over the ground, bend its back to reach forward with the hind paws, and then straighten the back to begin another stride with its fore paws. In this way, the feline is permitted a long stride for fast sprinting. However, such a strategy is a compromise. What a cat gains in speed it loses in endurance. The animal tires quickly and cannot run long distances because much of the forward force created by the hind limbs against the ground is lost to the flexibility of the vertebral column.
It is here that the ungulates have "found" their advantage. They are provided with stiff backbones that transmit the force of the hind legs against the ground into forward motion. Thus, although the animal cannot run as fast as its feline predator and does not have as long a stride, it can run farther. If it becomes aware that it is being stalked, it can outrun a would-be killer fairly handily. To aid in perceiving prey, ungulates have laterally oriented eyes, large ears, and a tendency to form herds in which some animals are keeping watch at any given time.
— Anne Nishijima, "Predator and Prey"
The purpose of this comparison, clearly, is to weigh the advantages and disadvantages of each type of animal. If, on the other hand, your purpose is to emphasize particular features, the information may be arranged according to the point-by-point method, as in the following example:
What is macho? That depends which side of the border you come from.
Although it's not unusual for words and expressions to lose their subtlety in translation, the negative connotations of macho in this country are troublesome to Hispanics.
Take the newspaper descriptions of alleged mass murderer Ramon Salcido. That an insensitive, insanely jealous, hard-drinking, violent Latin male is referred to as macho makes Hispanics cringe.
"Es muy macho," the women in my family nod approvingly, describing a man they respect. But in the United States, when women say, "He's so macho," it's with disdain.
The Hispanic macho is manly, responsible, hardworking, a man in charge, a patriarch. A man who expresses strength through silence. What the Yiddish language would call a mensch.
The American macho is a chauvinist, a brute, uncouth, selfish, loud, abrasive, capable of inflicting pain, and sexually promiscuous.
Quintessential macho models in this country are Sylvester Stallone, Arnold Schwarzenegger, and Charles Bronson. In their movies, they exude toughness, independence, masculinity. But a close look reveals their machismo is really violence masquerading as courage, sullenness disguised as silence, and irresponsibility camouflaged as independence.
If the Hispanic ideal of macho were translated to American screen roles, they might be Jimmy Stewart, Sean Connery, and Laurence Olivier.
—Rose Del Castillo Guilbault, "Americanization Is Tough on 'Macho'"
comparisons
Incomplete comparisons are a common advertising technique ("38% fewer cavities when you brush your teeth with Brand X"), but they are not appropriate in formal writing, where comparisons must be complete, logical, and clear. Comparisons must be complete; they must identify the two things being compared.
Comparisons must be logical. The things being compared must indeed be comparable. To make sure that a comparison is logical, check the two parts for parallel structure.
