In this article, I draw several lessons learned about how to assess student, classroom, and teacher effects, with a specific focus on performance-based teacher evaluations. One lesson is that hierarchical linear modeling techniques are helpful in sorting out the magnitude of impacts at these three different levels of the education system. The other major lessons are reflected in the conclusion that research findings suggest that educators have learned how to design and operate performance-based teacher assessments that have sufficient reliability and validity to use for consequential decisions such as triggering pay increases.