Are raters influenced by prior information about a learner? A review of assimilation and contrast effects in assessment.

Understanding which factors can impact rater judgments in assessments is important to ensure quality ratings. One such factor is whether prior performance information (PPI) about learners influences subsequent decision making. The information can be acquired directly, when the rater sees the same learner, or different learners over multiple performances, or indirectly, when the rater is provided with external information about the same learner prior to rating a performance (i.e., learner handover). The purpose of this narrative review was to summarize and highlight key concepts from multiple disciplines regarding the influence of PPI on subsequent ratings, discuss implications for assessment and provide a common conceptualization to inform research. Key findings include (a) assimilation (rater judgments are biased towards the PPI) occurs with indirect PPI and contrast (rater judgments are biased away from the PPI) with direct PPI; (b) negative PPI appears to have a greater effect than positive PPI; (c) when viewing multiple performances, context effects of indirect PPI appear to diminish over time; and (d) context effects may occur with any level of target performance. Furthermore, some raters are not susceptible to context effects, but it is unclear what factors are predictive. Rater expertise and training do not consistently reduce effects. Making raters more accountable, providing specific standards and reducing rater cognitive load may reduce context effects. Theoretical explanations for these findings will be discussed.