Once a course or lesson has been installed and is in process, the design takes over. Students and teacher (if there is one) and materials and the design rock back and forth and interact with each other in a ‘response environment’ for learning. If your decision-making has been good in creating this environment there is a good chance that it will have success. Your students will learn and will learn in a way that they like.
But, no designer can foresee and cater for every individual need. There will always be some on-the-spot-designing to be done: a left-handed sheep shearer is having difficulties in an exercise that has been written (unwittingly) for only right-handed sheep shearers; an educational visit to the Van Gogh museum in Amsterdam has allowed too little time for questions to which learners would like an answer; three medical students have bought microscopes of low quality — it is handicapping their work in cell biology; a singing teacher turns up at her Music Academy with a sore throat; one student in a class (who really wants to learn) can’t keep up with the rest. When a teacher is involved, she or he must take care of such things, and in doing so modify or extend the design. She or he must do some ad hoc on-the-spot designing.
The left-handed sheep shearer will probably best be helped by a joke about right-handed designers, and friendly personal instruction. The fans of Van Gogh need to be promised another opportunity for asking their burning questions. The medical students with the low-quality microscopes will need to negotiate with fellow students for the use of a good microscope for some of the critical laboratory tasks. The sore-throated teacher could perhaps substitute herself with a long-playing record. . . But when thinking about how you are going to use your intuition, logical thinking and creativity in doing any necessary on-the-spot designing, don’t forget that prevention is probably always better than cure. You must learn as a designer or teacher to look ahead and provide for safety first!
Designs for courses and lessons in which a teacher is not involved (eg self-study units) can have built-in remedial pathways to take care of on-the-spot design problems. The learner is informed about these pathways and is free to take them on her or his own initiative. Their existence offers the learner a special degree of control over the learning process. In making use of remedial pathways the learner is in fact doing a bit of on-the-spot designing for her or himself.