美国经典案例分析课件.ppt

第五章;What are test techniques?;What techniques do we need?;In this chapter we’ll discuss one technique, multiple choice. Then we’ll examine the use of techniques which may be used to test ‘overall ability’.;Multiple choice;What’s the most obvious advantage of multiple choice?;The difficulties with multiple choice are as follows:; A multiple choice grammar test score, for example, may be a poor indicator of someone’s ability to use grammatical structures. The person who can identify the correct response in the item above may not be able to produce the correct form when speaking or writing. This is in part a question of construct validity; whether or not grammatical knowledge of the kind that can be demonstrated in a multiple choice test underlies the productive use of grammar.; Even if it does, there is still a gap to be bridged between knowledge and use; if use is what we are interested in, that gap will mean that test scores are at best giving incomplete information.;2) Guessing may have a considerable but unknowable effect on test scores; The trouble is that we can never know what part of any particular individual’s score has come about through guessing. Attempts are sometimes made to estimate the contribution of guessing by assuming that all incorrect responses are the result of guessing, and by further assuming that the individual has had average luck in guessing. Scores are then reduced by the number of points the individual is estimated to have obtained by guessing.; However, neither assumption is necessarily correct, and we cannot know that the revised score is the same as (or very close to) the one an individual would have obtained without guessing. While other testing methods may also involve guessing, we would normally expect the effect to be much less, since candidates will usually not have a restricted number of responses presented to them (with the information that one of them is correct).;3) The technique severely restricts wha