The quality of teacher judgments about their students' achievements as a focus of research is connected with the question of how the quality of these judgments can be improved. A possibility of improving the quality is to make teachers aware of the great impact their judgments have. This means increasing accountability. To test the effects of accountability on teacher judgments, an experiment with the simulated classroom was conducted. In the simulated classroom, virtual students with different

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... mathematical ability were presented on a computer screen. Teachers assessed these students' ability after two simulated lessons. With this approach, systematic biases could be shown. Girls were assessed as less able in solving mathematical problems than boys with the same ability. However, for the increased accountability condition, only marginal significant effects resulted. When accountability was high, no differences in ratings for boys and girls with the same ability were observed.