The difficulty and discrimination of Chinese cognitive ability scale

Abstract

Objective To examine the difficulty and discrimination of the items in Chinese cognitive ability scale(CCAS).Methods By employing stratified sampling method,333(167 boys,166 girls) prospective subjects were recruited at random from the kindergartens,elementary schools or middle schools in both Wuxi and Wuhu City.Two classes in each school were enrolled in this study and 6 or 7 students were included randomlv with an age range of 6 to 16 years and females-male ratio of 1:1.All participants received no special education or related services.Demographieal date of each student undergone the CCAS were collected.Results 1.Difficulty:the difficulty of the iterms in the CCAS ranged from 0.00 to 1.00 and 60%of them ranged from 0.30 to 0.70.These resuits took normal approximation.2.Discrimination:in general 63% items of all the subtests were over 0.2.Thediscrimination of digit span subtest was 0.24, the spatial span was 0.22 and the rest ranged from 0.31 to 0.51.Conclusion The difficulty in all subtests is of reasonable design and the discrimination comes measurement to psychometric standard. Key words: Cognitive Ability; Chinese Cognitive Ability Scale(CCAS); Difficulty; Discrimination