Hammocking is a technique used in broadcast programming whereby an unpopular television program is scheduled between two popular ones in the hope that viewers will watch it, using the analogy of a hammock hanging between two strong and established trees. Also related is the concept of tent-pole programming, or using popular, well-established television shows scheduled in pivotal time periods to boost the ratings of the shows around them. Used especially for new shows, Hammocking is limited to prime time, where "appointment television" is strong. The main theory in play is that audiences are less likely to change channels for a single time slot. Presupposing that there are three available time slots, the weakest show would, under a hammocking strategy, be placed in the middle slot so that its lead-in, the show that airs before it, is a series popular enough to create a coattail effect when a viewer leaves the television on the same station; to keep people watching, another popular series is positioned in the lead-out slot after the weak show, so the viewer has reduced incentive to change the channel. These strategies depend on the general phenomenon of audience flow. The strength of the final program then presumably leads into the late local news, followed by late night programming, with the hope the channel remains unchanged after bedtime to allow a network affiliate television station to have strong ratings for its morning newscast leading into the network's morning show. This creates a halo effect with the schedule in general to build network and affiliate station loyalty with a viewer. Public broadcasting also uses this as a way to promote serious but valuable content. Hammocking may lead to situations where even if programs remain weak, audience rating will be high. However, there is a risk. If the middle show is too weak, the audience could change the channel altogether even if they “would have stayed if the two popular programs had formed a block.” Hammocking has been fairly reliable over the years. It was largely discovered by accident in the late 1950s: Michael Dann is credited with developing the concept after December Bride, thought to be a major hit at the time, under-performed when it lost its lead-in, I Love Lucy. Trying to hammock programs that have little in common with each other can have unusual consequences: TNBC, a block of programming NBC carried during the 1990s that had