Why can my child do things at home but not at preschool or school?

Being able to do something in one setting but not another is common. Preschool and school can have harsher conditions than home—more stimulation, tension, different procedures and people, fatigue. Rather than "can they really do it or not," seeing it as "under what conditions can they do it?" reveals the response. Sharing with the teacher the arrangements that work at home (prompts, step charts, models) so the same cues can be used at preschool helps them show their ability.