he writing conventions, meaning the expected style, of one discipline can vary greatly from those of another subject area. For example, you should write a literary analysis in the present tense ("The protagonist soon becomes . . .") in order to avoid awkward shifts from the present to the past tense as the analysis of a story progresses. However, in a lab report for a chemistry course, you should write the results section in the past tense ("The temperature changed . . .") because the experiment already has been completed.

There also are good reasons for many other differences in the writing conventions of various disciplines. For example, the MLA style of in-text citation does not include the date of publication, such as (Smith 125), because a respected literary critic from the nineteenth centyry still is considered to be a valid source in the humanities. In contrast, APA style citations include the date, as in (Smith, 1999, p.125), because social scientists want to indicate their use of the most current research.

There also is some agreement among conventions. To write both a scientific lab report and a literary analysis based on New Criticism, you should use the passive voice ("When the temperature was increased . . . "). References to "I" the student writer are avoided ("When I increased the temperature . . ." and "When I read this story, I felt . . .") in order to heighten the sense of objectivity, which suggests that the results do not depend on a particular person.