Arguments fall into two possible categories: deductive and inductive. A deductive argument uses two general statements (premises) to support a specific conclusion. (Theft is wrong. Plagiarism is theft. Therefore, plagiarism is wrong.) An inductive argument uses specific examples, data, or facts to support a general conclusion. (Nine out of ten doctors prefer Blammo pain pills.)

To evaluate or challenge a deductive argument, there are two key question to ask:

1. Does the conclusion logically follow from the premises?
2. Are the premises true?

To evaluate or challenge an inductive argument based upon experimental or survey data, examine the methods and the data:

1. Is the sample of data clearly described?
2. Is the sample large enough to support the conclusion?
3. Does the sample represent a typical cross section of the population or phenomenon studied?
4. Were scientific methods, such as the use of a control group, consistently employed?
5. Was the evidence presented and interpreted in an unbiased way?

To evaluate or challenge an informal inductive argument based upon examples, ask the following questions:

1. Are the examples sufficient to support the conclusion?
2. Does the arguer discuss the examples fairly and impartially?
3. Does the arguer overlook or misrepresent contradictory examples?

For more details, see "Making the Argument Develop" in chapter four of The Research Process.

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