In this chapter, the author sets out the work involved in obtaining such a measure. She describes the process involved in getting a reliable measure of goal-corrected empathic attunement. It was eventually achieved by clarifying the nature of what was being observed. The work of obtaining a reliable score involved developing a much more complex understanding of attunement, one which involved empathy, goal-correction and attachment theory. Attunement is more than mere mimicry of another’s state; it has as its reference the inner state of the other, their somatic experience of that state, and their cognitive and affective processes. The process of attending to the inner state of the other in this way demands intense concentration on verbal and nonverbal signals, including breathing, colour, tiny muscle movements in the face or hands, and other signs that indicate where the other person might be in themselves.