Downey R G, King C
Institutional Research andAnalysis, 226 Anderson Hall, Kansas State University, Manhattan66506.
J Gen Psychol. 1998 Apr;125(2):175-91. doi: 10.1080/00221309809595542.
The effects of using two methods (item mean and person mean) for replacing missing data in Likert scales were studied. The results showed that both methods were good representations of the original data when both the number of respondents with missing data and the number of items missing were 20% or less. As the numbers of missing items and of respondents with missing data increased for the person mean substitution method, a spurious increase in the inter-item correlations (and, therefore, reliability) for the sale was produced. The item mean substitution reduced the reliability estimates of the scale. These results suggest caution in the use of the person mean substitution method as the numbers of missing items and respondents increase.
研究了在李克特量表中使用两种方法（项目均值和个人均值）替换缺失数据的效果。结果表明，当缺失数据的受访者数量和缺失项目数量均为20%或更少时，两种方法都是原始数据的良好代表。对于个人均值替换法，随着缺失项目数量和缺失数据的受访者数量增加，该量表的项目间相关性（以及可靠性）出现虚假增加。项目均值替换降低了量表的可靠性估计值。这些结果表明，随着缺失项目和受访者数量的增加，使用个人均值替换法时应谨慎。
