Head teachers are the senior teachers at a school and are responsible for managing staff and setting policies for the school. The term "head teacher" is more often used in British Commonwealth countries, with "principal" or "headmaster" more often used in the United States. The term "principal" is a shortened version of "principal teacher," indicating the relationship between the roles. The head teacher often has part-time responsibilities for classroom teaching.
Head teachers motivate and lead their teaching staffs, evaluate their performance and set goals and expectations. Based on their extensive experience as teachers, they provide vision and leadership to a school and are ultimately responsible for keeping the school running smoothly. The presence of a good head teacher is key to the recruitment and retention of good teachers. Head teachers or principals often provide training to their staff. In addition, they often serve as the spokesperson for their school to parents and the community at large. They also often have some oversight over curriculum choices.
According to Wikipedia, studies show that effective head teachers improve student performance at their school, and ineffective head teachers have the opposite result. One of the key areas in which head teachers impact their schools is through their hiring and retention of excellent teachers.