This article details the development and methodological characteristics of the Systemic Therapy Inventory of Change (STIC), the first measurement system designed to assess change in family, couple, and individual therapy from a multisystemic and multidimensional perspective. The article focuses specifically on the developmental process that resulted in the five valid and reliable scales that comprise the core measure of the system, the INITIAL STIC, which is administered to clients just before beginning therapy. The scales focus on five systemic domains: individual adult, family of origin, couple, family, and individual child. This article describes the five system scales, the results of the factor analytic process that created them, as well as data on their convergent and discriminant validity.