Previous work has shown that students have persistent difficulties in understanding how central dogma processes can be affected by a stop codon mutation. To explore these difficulties, we modified two multiple-choice questions from the Genetics Concept Assessment into three open-ended questions that asked students to write about how a stop codon…

Considering scoring validity as encompassing both reliable rating scale use and valid descriptor interpretation, this study reports on the validation of a CEFR-based scale that was co-constructed and used by novice raters. The research questions this paper wishes to answer are (a) whether it is possible to construct a CEFR-based rating scale with…

This study examined the percentage of task-sampling variability in performance assessment via a meta-analysis. In total, 50 studies containing 130 independent data sets were analyzed. Overall results indicate that the percentage of variance for (a) differential difficulty of task was roughly 12% and (b) examinee's differential performance of the…