Case study construction in longitudinal perspective means to follow a single case across time based on the consecutive Faith Development Interviews (FDIs) and drawing on psychometric data. We regard the interviews as the focus of our current study. Therefore, in this chapter, we first look into the history of method development. Then, we present the basic method, the Faith Development Interview, and explain the structural evaluation according to the model of religious styles. Next, we turn to content, to what was said at different points in time in the domains of the FDI, to narratives and to key aspects already defined or newly emerging. Working in longitudinal perspective, we are interested in tracing change as well as stability. We do this by comparing the interviews obtained at the time of the original Deconversion Study (Streib, Hood, Keller, Csöff, & Silver, 2009)-in this volume referred to as Time 1-, and at the time of re-interviewing-here referred to as Time 2, which means after a time span of about 10 years. These are interpreted against the background of the differences and similarities of psychometric profiles obtained at both points of measurement. As an outlook, we discuss ongoing methodological innovation and how to balance this with continuity in longitudinal research.
4.1The Faith Development Interview: A Short HistoryThe Faith Development Interview was designed by James Fowler (1981) and his team , DeNicola & Fowler, 1993. The theory underlying this instrument is based on Fowler's broad concept of "faith. " Fowler, with reference to Cantwell Smith (1963, 1979), defined "faith" as a person's constructions and reconstructions of everyday experience in light of the ultimate conditions of existence, thus as ways of meaning-making in response to transcendent centers of value and power (cf. Fowler, 1981, p. 92-93). This conceptualization of "faith" is very broad, open, and inclusive-aiming at a kind of common core of the various religious and worldview traditions, embracing theistic and non-theistic worldviews, and also ways of apparently non-religious meaning-making. This is different from "religion, " which, according to Cantwell Smith, designates the cumulative traditions (institutions, texts, religious traditions) and from "belief, " which means consent to