The mission statement is the conceptual foundation of an organisation. It sets an organisation's purpose by describing what the organisation does and what it stands for. A mission statement should be more than a public relations slogan, it should convince any reader that the organisation has a reason to exist.
When writing a mission statement it is important to consult widely to get a range of ideas from those who think about the organisation in question. This ensures that not only do people feel that they have contributed to the mission statement but also that the final product reflects a broad consensus rather than just the obsessions of the executive.
Then writing the first draft of the mission statement should be left to two or three people rather than a committee. Those writing the draft should seek to craft a simple and direct statement that does not make grandiose claims but makes the organisation's purpose clear.
Then the draft mission statement should be subject to broad discussion and when the content is agreed, the final draft should be left to one or two people with instructions to turn the conclusions of the debate into natural language.
From the mission statement many organisations generate aims which are the proposed outcomes that would meet the purpose expressed in the mission statement. From the aims, strategic objectives are generated that describe the particular targets required to realise those aims.