This article describes the affordances of using clinical interviews with struggling mathematics learners to inform intervention and instruction. A case study of a fourth grade student, Danny, is presented to give an illustrative example of the complexity of the student's mathematical understandings in terms of place value. From the clinical interview, there were many skills where Danny exhibited relative strength. He was able to read numbers into the millions without pausing or making errors. He could count by ones, tens, fives, and hundreds, and count backward by fives. These relative strengths could be perceived as an understanding of place value. However, the clinical interview reveals a much deeper and nuanced report of Danny's place value conceptions, preconceptions and misconceptions. Implications for multidimensional assessments are discussed. (Contains 6 figures.)