Early efforts to apply knowledge of dialect differences to reading stressed the importance of the distinction between differences in pronunciation and mistakes in reading. This study develops a method of estimating the probability that a given oral reading that deviates from the text is a true reading error by observing the semantic impact of the…

Rater errors (rater severity, halo effect, central tendency, and restriction of range) are described, and criteria are presented for evaluating rating quality based on a many-faceted Rasch (FACETS) model. Ratings of 264 compositions from the Eighth Grade Writing Test in Georgia by 15 raters illustrate the discussion. (SLD)