Attachment theorists claim that the quality of parental support is internalized as a mental representation of early relationship experiences. Increasingly, the content of attachment representations is evaluated by studying the extent to which adults demonstrate knowledge of the secure base script , either in the context of the Attachment Script Assessment (ASA) or during the Adult Attachment Interview (AAI sbs ). Preliminary evidence from a high-risk sample showed that AAI sbs was more strongly associated with the quality of antecedent caregiving than was the more traditional approach to the measurement of adult attachment focused on the coherence of adults' AAI discourse (Waters, et al., 2017). Drawing on new coding of data from the NICHD Study of Early Child Care and Youth Development (SECCYD), we found that AAI sbs around age 18 years was significantly predicted by observations of maternal ( r = .21) and paternal ( r = .12) sensitivity assessed prospectively through age 15 years, and with attachment security in the first three years of life ( r =.08). AAI sbs was also associated with existing measures of adult attachment ( r s = .31-.42). Pre-registered analyses revealed that AAI sbs performed in a manner roughly comparable to traditional, though more labor intensive approaches to coding the AAI. Based on all available evidence from the SECCYD and the pragmatic challenges and advantages of different narrative methods for assessing adult attachment representations (Booth-LaForce & Roisman, 2014; Steele et al., 2014), researchers seeking to measure attachment representations should strongly consider the strengths of the ASA in term of practicality, performance, and adaptability to various age groups across development (Waters & Waters, 2021).