RUNNING HEAD: Reliability and Validity Coefficients Reliability and Construct Validity Coefficients Adjusted for Correlation within Family Dyads

The assessment of reliability and construct validity for scales used to evaluate families is potentially limited because standard coefficients are not computed appropriately using the combined responses for family members due to their possible intra-familial correlation. In this paper, we describe and demonstrate the use of linear mixed modeling to compute generalizations of such coefficients for item and scale responses for family dyads. These include generalizations of coefficients for construct validity correlation, differential reliability index, internal consistency reliability, item-total correlation, and test-retest reliability. Example analyses are presented using survey responses from parents of a child with a chronic condition that focus on family management of the child's condition.