It often involves travel and close quarters with unfamiliar people in unfamiliar surroundings. The unfamiliarity can be a distraction and can discourage free exchange of ideas. Being away from the classroom can also be a source of anxiety. When substitutes don't do their jobs well, teachers come home to extra work. Reality is not that simple.
Effective teaching involves a long-term process of trial and error in the classroom.
Moreover, simply giving teachers information, however useful, rarely changes the way they teach. Speaking off the record, most teachers will admit that when they return from professional development sessions they pick up right where they had left off. Given the high cost and ineffectiveness of many professional development models, it is obvious that successful education reform will not be brought about by more of the same. What are urgently needed are delivery methods for teacher professional development that are economical, flexible, convenient, adaptable to individual differences, and responsive to the complexities of classroom teaching. Pioneering experiments in Texas and Illinois have demonstrated that the World Wide Web can be an effective medium of delivery for teacher professional development.