The main function of the Discussion is to answer the question(s) posed in the Introduction. Other important functions are to explain how the results support the answers and how the answers fit in with existing knowledge on the topic.
The last step in the story line comes at the beginning of the Discussion. In a hypothesis-testing paper, the last step is the answer to the question (whether the hypothesis is true or false). In a descriptive paper, the last steps are a restatement of the message (for example, the key features of the structure described) and the implication (the structure's function). In a methods paper, the last steps are a restatement of the new method, its advantages and disadvantages, and its applications. In this chapter, we focus on the Discussion section of hypothesis-testing papers.
In a hypothesis-testing paper, the Discussion includes the answers to the questions posed in the Introduction and any accompanying support, explanation, and defense of the answers. In addition, the Discussion includes explanations of any results that do not support the answers; indications of the newness of the work; explanations of discrepancies with others' results; explanations of unexpected findings; explanations of limitations of the methods, of weaknesses in the study design, or of the validity of assumptions; and indications of the importance of the work.
The answer should answer the question exactly as it was asked, using the same key terms, the same verb (when appropriate), and the same point of view. The verb should be in present tense, because the answer should be true for the whole population from which your study population was drawn. For example, if the question was "Does sympathetic stimulation increase norepinephrine synthesis in rat superior cervical ganglia in vivo?" the answer would be either "This study shows that sympathetic stimulation increases norepinephrine synthesis in rat superior cervical ganglia in vivo" or "This study shows that sympathetic stimulation does not increase norepinephrine synthesis in rat superior cervical ganglia in vivo." Permuting the key terms or the verb or changing the point of view would make the answer more difficult to recognize.
Before the answer is stated, it should be signaled, so that the reader knows it is the answer. Some signals of the answer are listed below. The verb tense used in the signal of the answer depends on the subject of the sentence. If the subject is "study" or "results," the verb in the signal of the answer is in present tense. If the subject is "we," the verb in the signal is in present, present perfect, or past tense, depending on the verb.