差异分数的信度分析

本文提出差异分数的信度变化问题，并以模拟数据分析了差异分数的信度在不同情况下的变化规律。结果指出：1．当两次测试得分的信度系数相等或相近时，两次测试的标准差相差越大，差异分数的信度越高。2．当两次测试得分的信度系数不等时，只要两次施测中任何一次的信度和标准差同时大于另外一次，那么差异分数的信度也比较高。3．无论两次测试的信度关系如何。两次测试相关越低，差异分数的信度越高。

The Reliability of Difference Score

This paper discusses how the reliability of the difference score changes in different conditions of test parameters. The results show that 1)The reliability of difference score is sensitive to variations of difference between the two standard deviations while the two testings' reliabilities are equal or similar. 2)When they have unequal reliabilities, the reliability of difference score will be high if the reliability and variability of any of the two testing situations are simultaneously greater than those of the other situation. 3) The lower the correlation of the two testings,the higher their reliability of difference score.