Development of an observational instrument to measure mother-infant separation post birth.

The importance of the timing, quality, and quantity of early maternal-infant contact has gained prominence over the years. However, no researcher has adequately documented the nature of maternal-infant contact and separation. This study assessed the psychometric properties of the Index of Mother-Infant Separation (IMIS), pronounced "I miss," which is a 37-item observational measure of the process of mother-infant contact or separation post birth. Assessment of reliability and validity of the IMIS was conducted using data collected in a randomized clinical trial with 224 healthy newborn infants assigned at 1 hour post birth to self-regulatory or routine nursery care (control) groups. Time-sampled observations occurred every 15 minutes. Content validity indices of the IMIS, determined by nine nationally known perinatal experts, were 77% to 100% for instrument items. Construct validity was supported through known-groups hypothesis testing (p < .0001). Interrater reliability was from 86% to 90%. The IMIS is a valid observational measure of maternal contact when raters are trained to score it reliably.