Lesson structure (organization in terms of meaningful relationships among ideas or concepts) is a low-inference indicator of lesson organization in that it can be observed and objectively quantified. It affects achievement positively, and students generally rate lessons higher when the structure of the lesson is relatively high. Teachers vary in the degree of structure of their lessons, a fact indicating that some teachers could profit by being trained to increase the degree of structure, or commonality of ideas and concepts, in their lessons. Problems have been identified in the training process and in analyzing lesson structure, but these problems can be resolved by expending time and by employing subject matter experts. The most relevant suggestion for teacher training and teacher evaluation is that trainers and evaluators focus on low-inference teacher behaviors that can be critiqued objectively. Clusters of such behaviors may provide a key for developing useful theories of instruction. (Author/JD)