A graveyard slot (or death slot) is a time period in which a television audience is very small compared to other times of the day, and therefore broadcast programming is considered far less important. Graveyard slots are usually in the early morning hours of each day, when most people are asleep. Because there is little likelihood of having a substantial viewing audience during this time period, providing useful television programming during this time is usually considered unimportant; some broadcast stations go off the air during these hours, and some audience measurement systems do not collect measurements for these periods. Some broadcasters may do engineering work at this time. Others use broadcast automation to pass-through network feeds unattended, with no one outside of broadcasting authority-mandated personnel and emergency anchors/reporters present at the local station overnight. A few stations use "we're always on" or a variant to position their 24-hour operation as a promotional selling point, though as this is now the rule rather than the exception it was in the past, it has now mainly become a selling point for a station's website instead.
The most well-known graveyard slot in most parts of the world is the overnight television slot, after late night television and before breakfast television/morning show (between 2:00 AM and 6:00 AM). During this time slot, most people that are at home are asleep, and most of those that are awake are either at work, away from the television, trying to fall asleep, or just returning home from a bar and too intoxicated to pay attention, leaving only insomniacs, intentionally nocturnal people, and irregular shift workers as potential audiences. Because of the small number of people in those categories, the overnight shift was historically ignored as a revenue opportunity, although increases in irregular shifts have made overnight programming more viable than it had been in the past. In the United States, for example, research has shown that the number of televisions in use at 4:30 AM doubled from 1995 to 2010 (8% to 16%).