The major concern is whether a student learns a skill or concept. When the skill is learned is important, but it is not the primary limiting factor. Experience reduces fear and increases confidence, setting the stage for gaining knowledge and becoming competent. Blind children need real world experiences to provide the foundation for concept development. Classroom discussions or simulations do not always transfer to the real world.
All knowledge starts with experience.
The final stage is demonstrated competence. Mobility specialists require students to demonstrate mastery of objectives. No blind student gets a C grade in street crossing skills from a mobility teacher. Blind children must cross every street safely, every day. The three outcome levels roughly correspond to developmental ages.