The SAMR model is a tool for determining how you, the teacher, is using and accessing technology with your students. It is not a checklist or a sequential list. There may be days when you are using technology as a "tool substitute" in your classroom as well as days when you are redefining tasks and learning. "Where you are" on the SAMR model is not as important as "how technology can be used for THIS task."
"SAMR, a model designed to help educators integrate technology into teaching and learning , was developed by Dr. Ruben Puentedura. The model aims to enable teachers to design, develop, and integrate digital learning experiences that utilize technology to transform learning experiences to lead to high levels of achievement for students."
(Quote from: http://msad75summertechnologyinstitute.wordpress.com/beyond-substitution/)