Probe into the Automatic Score of Subjective Items Based Upon Computer-Assisted Assessment

In allusion to the hot and difficult problem of computer-assisted assessment, in order to improve the function of computer-assisted assessment system, in this study, a new assessment method is presented to realize the automatic score of subjective items. To perform the assessment, it is necessary to establish a repository of reference answers written by course instructors or related experts. Then focused on how to use the BLEU algorithm to assessment, and through the n-gram processing, this paper improved the algorithm in the synonyms and spelling errors, etc. Applied the modified version of the BLEU to identify the most similar reference answer to the student answer and then the student answer is scored on its similarity with the selected reference answer. At last, through one empirical research we proved the availability of the new evaluation method. The results showed that,combined with the existing relatively mature evaluation method, this method can be used to for subjective answers assessment, and play a more active role in CAA.