Competitive dance is a popular, widespread activity in which competitors perform dances in any of several permitted dance styles—such as acro, ballet, jazz, hip-hop, lyrical, modern, and tap—before a common group of judges. This is in contrast with other activities that involve competition among dancers based on purpose, or specific dance style, such as pom squad and dancesport. The competitive dance industry largely consists of competition production companies—also sometimes called dance competition companies—that conduct regional competitions at stops along their annual, nationwide tours. Dancers who compete at these regional competitions are students ranging in age from approximately four to eighteen years old. Dance schools (often referred to as dance studios) arrange for their classes to compete as groups. Advanced dancers may be chosen to compete solos, duets, trios, or in a small group dance in addition to or in place of large group routines. Competitions typically begin in January and end in July or August.