Background: This study evaluated the psychometric properties of a new, comprehensive measure of knowledge about genomic sequencing, the University of North Carolina Genomic Knowledge Scale (UNC-GKS).
Methods: The UNC-GKS assesses knowledge in four domains thought to be critical for informed decision making about genomic sequencing. The scale was validated using classical test theory and item response theory in 286 adult patients and 132 parents of pediatric patients undergoing diagnostic whole exome sequencing (WES) in the NCGENES study.
Results: The UNC-GKS assessed a single underlying construct (genomic knowledge) with good internal reliability (Cronbach's alpha = 0.90). Scores were most informative (able to discriminate between individuals with different levels of genomic knowledge) at one standard deviation above the scale mean or lower, a range that included most participants. Convergent validity was supported by associations with health literacy and numeracy (rs=0.41-0.46). The scale functioned well across subgroups differing in sex, race/ethnicity, education, and English proficiency.
Discussion: Findings supported the promise of the UNC-GKS as a valid and reliable measure of genomic knowledge among people facing complex decisions about WES and comparable sequencing methods. It is neither disease- nor population-specific, and it functioned well across important subgroups, making it usable in diverse populations.
Keywords: genomic sequencing; informed decision making; knowledge; whole exome sequencing.