The Scale Score Transformation Issues of the BCTEST
Two issues of BCTEST scale scores were investigated in this study. The first of them is that the scale score an examinee will receive when he/she correctly answers all but one items is five or six points less than the examinees who get all items correctly. Some suggest that the rank order of examinees would be different if scale score had been one or two points higher for those who nearly get all items correctly. The second issue is that the scale score for the examinees who answered only a few items correctly tend to be the same, always 1. The purposes of this study are to investigate the effect of adjusting the scale score conversion table on the rank order of examinees' total score and to explore if the ability parameter obtained from the IRT calibration could be used to construct a meaningful score scale. The results indicated that at least 14.3% of examinees would be ranked differently when the scale score conversion table for one of the five subjects was modified. And it seems that the ability estimate given by 1PL model can be linearly transformed into 1-60 scale scores, although further adjustment is needed. For using the ability estimate obtained by 3PL model to form the scale scores, there still are some difficulties needed to overcome.
|關鍵詞||量尺分數、試題反應理論、基本學力測驗、Scale score、Item response theory、BCTEST|