Establishing nuanced interpretations of student thinking is central to formative assessment but difficult, especially for preservice teachers. Learning progressions (LPs) have been proposed as a framework for promoting interpretations of students' thinking; however, research is needed to investigate whether and how an LP can be used to support preservice teachers' interpretations. This article reports a study of two pairs of preservice physics teachers (PSPTs) working with video-based evidence of student thinking with and without an LP for force and motion. The PSPTs' discussions were video-recorded and investigated in terms of PSPTs' interpretations of student thinking: how they analyzed evidence of student thinking and identified implications for future learning. The PSPTs used the LP to focus attention on relevant aspects of student thinking and to begin to think about implications for student learning in a more step-like fashion, but did not use the LP to make sense of confusing student thinking or to draw specific implications for future learning. Recommendations for use of LPs in preservice teacher education are discussed.