Rater bias in the EASI temperament scales: A twin study.

Abstract
Under trait theory, ratings may be modeled as a function of the temperament of the child and the bias of the rater. Two linear structural equation models are described, one for mutual self and partner ratings, and one for multiple ratings of related individuals. Application of the first model to EASI temperament data collected from spouses rating each other shows moderate agreement between raters and little rating bias. Spouse pairs agree moderately when rating their twin children, but there is significant rater bias, with greater bias for monozygotic than for dizygotic twins. MLEs of heritability are approximately .5 for all temperament scales with no common environmental variance. Results are discussed with reference to trait validity, the person–situation debate, halo effects, and stereotyping. Questionnaire development using ratings on family members permits increased rater agreement and reduced rater bias. (PsycINFO Database Record (c) 2016 APA, all rights reserved)