The basic purpose of a compare and contrast essay is to analyze the differences and similarities of two given ideas or things. It is the writer’s job to provide evidence showing the factors that each topic has in common as well as providing evidence to show how they differ from one another. The writer will often find these types of essays when trying to synthesis information on a broad scale, such as in a government class. Essentially, it is the job of the writer to show the reader the points of commonality between the topics and to point out the differences.