Sister shows are two or more
television shows which exist in the same
fictional universe and which may have
crossovers. They differ to a degree from
spin-offs in that shows may air simultaneously, rather than being derived from, and replacing, another. The popularity of most shows is limited to a few seasons, and sister shows allow expanding the immediate audience and ratings share. This is accomplished by using mostly different actors and production facilities. Sister shows often shift styles or target audience slightly, for a larger overall market. Thus
The Beverly Hillbillies emphasizes
slapstick, while
Green Acres emphasizes
surreal humor.