Whether you're a fifth-grade student, in graduate school or an established engineer, the foundational purposes for writing a persuasive or proposal essay are the same. At the heart of both essays lies the purpose of winning acceptance from your audience, but the kind or type of acceptance varies. A persuasive essay is meant to convince the reader of a certain point or stance and get him to accept the view you put forth. A proposal essay, on the other hand, is meant to convince the reader that the idea, activity, purchase or other action you are suggesting is warranted. Here, the purpose is to get the reader to accept and grant acceptance for the action you want to put into effect.
The objectives of persuasive and proposal essays are tied to their purposes. Both essays seek to win over the reader and get him or her to accept and agree to your viewpoint or suggestion. Persuasive essays are best for topics that are controversial in nature and where two or more opinions on the topic already exist. The writer's objective is to present all the facts, including pros and cons from all viewpoints, and then conclude with strong, emotional or philosophical remarks that convince the reader to adopt your perspective and agree with you. With proposal essays, the writer's objective is to clearly present an idea, bid or request, and then support it with a justified rationale for who would benefit from the suggestion and why. Proposal essays can be written to suggest a topic for a longer research paper, to offer professional services, to implement a new rule in the workplace or to justify a work-related purchase or expense.
As with all forms of writing, your audience will help determine which kind of essay you should write. For the administrative assistant seeking a new time-keeping procedure, a proposal essay to the board of executives explaining the proposed procedure and necessity for the change would be far more effective than a persuasive essay seeking to convince the board that the current procedure for collecting time sheets is not Earth-friendly. Stick with persuasive essays when you simply want to change someone's mind and proposal essays when you want your audience to take a specific action.
Acceptable, effective writing styles for persuasive and proposal essays vary greatly. For persuasive essays, your tone should be authoritative and your facts should be compelling. Use descriptive, figurative and emotionally-charged language to underpin the facts, emphasize points, illustrate examples and persuade your reader to respond emotionally or morally. You want your reader to see and feel the way you do about a passionate topic. Proposal essays, on the other hand, should present information in a formal and unbiased manner. Information should be plainly and clearly stated, and a logical rationale that practically explains the "hows" and "whys" of your argument should follow. Facts, statistics, research findings and other forms of evidence should be presented without emotional verbiage attached. You want your reader to see how your suggestion is beneficial despite your own perspective, not because of it.