A study examined how teacher educators' goals, objectives, and class procedures were affected by using portfolios to promote critical thinking about teaching and learning, and how these instructional decisions were mediated and negotiated by the socio-professional context. Six teacher educators implementing a pilot portfolio program recorded their reflections and responded to one another in a common journal (a "polylog"), in which each shared information and insights about instructional decisions, feelings, students' responses, and continued professional reading as the portfolios were being developed and evaluated. These transactions were analyzed collaboratively by the six researchers who used reflexive data analysis techniques and analytic induction to generate categories and other emerging patterns. The students' portfolios were analyzed by each professor for evidence of reflective growth and practice using the same methods. A model representing three concurrent, interrelated, and overlapping dimensions was developed: (1) instructional reflection and decision-making by each teacher (inquiring, futuring, acting, remembering); (2) collaborative, reciprocal links among the colleagues who are each involved in that process; and (3) spiraling, recursive cycles of increased risk-taking, both by the individual teachers and by groups. Findings suggest that the primary contribution of the model is its integration of collegial collaboration with a reflective teaching cycle, which is usually thought of as an individual decision-making process. (One figure representing the model is included, and 26 references are attached.) (RS)