Using the method of pairwise comparison to obtain reliable teacher assessments

Abstract

Demands for accountability have seen the implementation of large scale testing programs in Australia and internationally. There is, however, a growing body of evidence to show that externally imposed testing programs do not have a sustained impact on student achievement. It has been argued that teacher assessment is more effective in raising student achievement levels. However, it is also often argued that teacher assessments are less reliable than the results of testing programs. This paper presents a study in which teachers judged writing scripts using the process of pairwise comparison to generate a scale. The analysis showed high internal consistency of the teacher judgements. The scale locations from pairwise comparisons were highly correlated with scale estimates for the same students from a large-scale testing program. The results demonstrate it is possible to efficiently obtain highly reliable and valid teacher judgements using the process of pairwise comparison. Reliability indices are also provided for a series of small-scale assessments that used the same methodology in a range of other domains. The results support the findings of the main study. The article discusses the benefits of using the method to supplement and validate results from large-scale testing programs.