Identifying And Controlling Writing Task Difficulty Factors In English Tests

Researches on the testing of writing mainly focus on the construct of writing and scoring reliability, but research on the designing of writing tasks, especially the difficulty of writing tasks is rather infrequent. In fact, the difficulty of writing tasks is of great influence on the quality of a writing test. According to Bachman, only when the difficulty is positioned at an appropriate level can test scores offer the most information, and too high or too low a difficulty will both exert negative influence on the meaning of scores. From a psycholinguistic point of view, too low a difficulty will decrease test-takers'motivation, which will in turn prevent them from demonstrating their highest writing ability. Besides, even if all writers make the best use of their ability, chances are that the scores are all very high, which will lead to very low discrimination. On the other hand, if the task is too difficult, test-takers may also lose interest, and most writers will not be able to write well even if they want to. The result is again that test takers will not be able to demonstrate their best writing ability. Therefore, it is clear that only when writing tasks are so designed that present test takers with appropriate challenge can the test achieve the maximal usefulness.The major purpose of this dissertation is to explore factors that influence the difficulty of writing tasks in test of English as a foreign language, and on the basis of such findings suggest possible ways to control these factors. As writing ability is under the influence of multitudinous factors and as personal traits of test-takers may vary in unlimited ways, it is impossible to exhaust all the factors that may influence the difficulty of writing tasks. Given such considerations, the research can only be confined to some major factors on the basis of extensive literature study. Such factors include test-takers'language proficiency, topical knowledge, discourse mode knowledge, task prompt as well as time constraint. As for the research method, the research relies on both literary research and empirical study. In major chapters of this dissertation, research findings and a hypothetical model of task difficulty concerning...