Scheduling.

Scheduling is important for documentaries, and even though we now live in a digital age, scheduling still needs to be considered and appropriately chosen.
Pre-echo - this means that a documentary is shown before a popular show. This is in order for people to turn to the channel before the regular programme so that they don't miss it, and by doing this, are able to watch the documentary.
Hamacking - this is when a documentary is placed inbetween two popular shows. This is especially good timing as a viewer is less likely to change the channel between two programmes that they want to and regularly watch.
Inheritance - this is when it is placed after a popular show. This too is very good timing as after a show that has been watched, people sometimes have no need to change the channel and leave the one that they were watching on, therefore having the documentary shown.