The Aims of Documentary
This is by no means exhaustive, but it is a starting point for your own research.
To deliver audiences to advertisers. (and do it cheaply)
Even BBC docs have spin off books and may involve sponsorship deals BBC Bitesize books, Ellen Mac Arthur's Kingfisher had BT Logos.
Commercial channels can use scheduling to pull an audience with a particular interest. Dieting Doc followed by Perfect Breasts carried lots of health related advertising early on in the evening. Clearly a particular doc might pull a niche audience just as an interest magazine does.
In that some documentaries might be expected to attract an educated audience. They are also likely to be an affluent audience. (ABC1s)
To Entertain.
Documentaries are increasingly doing this. It perhaps began with the Drama-Doc, then the Docu-soap hybrid and has continued with other hybrids (the Docu-gameshow Big Brother, Bare Necessities) 'experiments' (Castaway 2000) and other programmes now being referred to as Reality TV. We are invited to observe people “improvising around the theme of being themselves (Andy Hamilton in the Hugh Weldon lecture) in carefully constructed, 'artificial' situations.
Other, more traditionally constructed docs have an element of entertainment. Perfect Breasts was in invitation to look at women's breasts (a pleasure associated with tabloid journalism) squirm at the sight of surgery (a gratification not dissimilar to watching gory slasher fiction) and shout “Bimbo” at the screen - there was no reference to breast implants in older women, or reconstructive surgery after cancer. There weren't even statistics about what percentage of 'teens' had implants, yet our first impulse might have been to categorise this doc as informative because it seems to be suggesting a worrying trend!
Even the good old expository mode Wildlife doc uses voice over to entertain with narrative conventions (suspense is an obvious one - will the lion get the baby deer? And 'the chase'. Non-diegetic music is usually added to increase the excitement. A lot of sex and violence!)
To Educate
Some educational docs have a niche audience (third year physics with the Open University, GCSE BBC Bitesize) These often deliver parts of a study course with a recognised qualification at the end of it. Generally they are scheduled in the middle of the night and videoed by their target audience.
Other docs also have educational elements but less well defined educational aims. (Natural History Docs and Science Docs increase your 'general knowledge') incidentally over a period of time they, to some extent, determine the hierarchy of knowledge / what is viewed as 'general knowledge.' (Knowing the bus timetables of Britain makes you a 'sad geek', knowing football scores back to 1960 is more 'respectable', knowing kings and queens of England is 'academic' and respectable - all involve the same brain activity.)
These documentaries are usually referred to by the type of material they contain (just as non-fiction books might be) eg. Science, Medical, Natural History, Psychology, The Arts, History.
To provide a channel with 'quality' status (TV documentaries)
Because documentaries are associated with 'reality', knowledge, 'serious' concerns they carry associations of 'quality' (like broadsheet newspapers) A channel hoping to be seen as 'quality' can signal this by buying, commissioning or making documentaries. Remember, the BBC has to justify the Licence fee with quality and mass market appeal, and commercial channels have to deliver audiences to advertisers.)
To inform
Grierson began with this intention. He hoped to inform the American public in order that they might be better able to make informed decisions when voting - democratic intentions?
This idea of information for citizenship or social responsibility in a 'global village' still exists.
Docs are used for this, often Left wing purpose, of informing the public of social inequality. Exposing social ills. But do they sometimes confirm stereo-types of 'dole-dossers' or 'inept starving Africans'?
Docs highlighting the state of British prisons might inform people about: conditions that affect the way they vote, prompt them to write to MPs or simply inform them how their taxes are spent.
Docs like Holidays from Hell inform people of their consumer rights.
Of course this raises issues of representation. Who is informing whom of what and why? So, a doc seeming to expose the inept holiday providers may in effect raise the profile/social importance of holidays (acting like a promotion) so that ultimately more people take holidays and the leisure industry benefits (even the 'dodgy dealers' get their share of a larger market)
Docs on health/personal issues might inform people about illnesses and conditions which prompts greater levels of understanding but are they sometimes strengthening stereo-types of 'helpless disabled victims'? Often these docs end with helpline contact details. You could argue this aims to provide advice or that it makes producers seem responsible and detracts from potential criticisms that they are making cheap minutage, mass appeal TV out of people's misfortune.
To document 'significant' events
Again it is worth considering who/what determines the 'significant'. Hitler had docs of his rallies shot - clearly the purpose here was propaganda, but the 'significant' might be determined by more insidious, institutional issues eg. The BBC has lost the right to show football matches so it is looking for other sporting events. They send Ellen Mac Arthur to sea with seven cameras knowing that the footage she collects can be used on the news to make her race seem like a significant event (self-fulfilling stuff ie. it must be important because it's on the news) and once they have created an interest they can trailer their doc on the news and guarantee an audience for it. They don't have to pay researcher, a journalist, a film crew. They collect a couple of aerial shots in a helicopter fly by, do the editing, add a bit of Dido's 'Until you're resting here with me' and Ellen delivers forty hours of footage to edit down to fifty mins - very cheap and the footage is used on both the BBC News and the Doc - a bargain. (and an exclusive.)
The making of a Media text can lead to a documentary spin-off which, while educating about the Media, also acts as a promotional vehicle for the film/album/festival./documentary even!
Likewise, the easy availability of existing news footage/ 'authentic' or period footage may mean that cheap documentaries can quickly be constructed by adding a voice-over, a few interviews with: eye-witnesses or 'experts', or the 'man on the street'. Eg. There are lots of Docs about the Nazi Holocaust not only because the Jewish community is influential and wants us to remember, but also because there's lots of easily available footage (more recent mass genocides involve paying researchers to go to dangerous places and investigate - not cheap)
To be a window on the world/ documenting ordinary events
This clearly raises issues of representation. Even with fly on the wall techniques, or the more recent, 'live' webcam, decisions are made about where to put the camera. Selection of subject and 'characters' are important and in edited texts the selection of images and cutting of sound and addition of non-diegetic sound are all important issues.
Who is being represented by whom? How representative are the selections that have been made? (statistically?) How might audiences read these representations? Representation is arguably more important in documentary than it is in fictional texts because audiences assume they are seeing representations of 'reality'. It is difficult for such documentaries to challenge our cultural expectations because in order for them to be received as 'windows on the world' the documentary must match its constructed 'reality' to the 'reality' which is taken for granted.
Docs of ordinary lives might: celebrate the working lives of 'ordinary people'; provide audiences with a sense of community or a measure of their own lives: identities and values; and/or provide escape (like wildlife docs, if narrative is provided then the uses and gratifications associated with fictional narratives will also apply)
To provide one person's view
Authored docs
(most commonly making use of a voice over and therefore expository in mode) provide a document of one person's view of 'reality' This is sometimes an 'expert' opinion. It is ironic that while authored docs are partly free from the constraints of impartiality, it could be argued that this is the most reliable of documentary forms because it doesn't purport to be anything other than subjective. In the hands of a powerful political leader however, this can become propaganda.
To document one person's life
These include: a biography of a celebrity or public figure (often expository or drama-doc in mode and sometimes 'historical'); one person's 'heroic struggle with' a debilitating disease; an expose of a corrupt public figure (often, but not necessarily, expository mode, sometimes involving the use of hidden cameras).
