ESTIMATING THE RELIABILITY, VALIDITY, AND INVALIDITY OF ESSAY RATINGS |
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| Authors: | H BLOK |
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| Institution: | Stichting Centrum voor Onderwijsonderzoek, Amsterdam |
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| Abstract: | In an essay rating study multiple ratings may be obtained by having different raters judge essays or by having the same rater(s) repeat the judging of essays. An important question in the analysis of essay ratings is whether multiple ratings, however obtained, may be assumed to represent the same true scores. When different raters judge the same essays only once, it is impossible to answer this question. In this study 16 raters judged 105 essays on two occasions; hence, it was possible to test assumptions about true scores within the framework of linear structural equation models. It emerged that the ratings of a given rater on the two occasions represented the same true scores. However, the ratings of different raters did not represent the same true scores. The estimated intercorrelations of the true scores of different raters ranged from .415 to .910. Parameters of the best fitting model were used to compute coefficients of reliability, validity, and invalidity. The implications of these coefficients are discussed. |
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