  Very little is known about how the nature of expertise in introductory and
advanced courses compares in knowledge-rich domains such as physics. We develop
a framework to compare the similarities and differences between learning and
patterns of student difficulties in introductory physics and quantum mechanics.
Based upon our framework, we argue that the qualitative patterns of student
reasoning difficulties in introductory physics bear a striking resemblance to
those found for upper-level quantum mechanics. The framework can guide the
design of teaching and learning tools.
