The advocacy letter is written as a letter, so you need to format it as such.
Date
Address of Recipient
Salutation
Introduction
Writer identifies himself or herself.
Briefly describes the issue and the writer’s vested interest in it
States the writer’s position and the action you want the stakeholder (audience to take) and why that action is a worthy one.
Body paragraphs
Background information (if needed–the stakeholder (audience) will determine how much information is needed)
Argumentation, with cited evidence
Concession, counterargument, and refutation
Conclusion
Reaffirm the writer’s position and show respect for the stakeholder’s (audience’s) position
Signature
Sign the letter with your name
Tone and Evidence
Advocacy letters do not insult the stakeholder by providing information that is already well known
Advocacy letters do not permit ad hominem attacks, ultimatums, exaggerations, or lies. Personal experience may or may not be relevant. When in doubt, stick to evidence-based claims.
Advocacy letters use evidence the stakeholder will respect. If you think the CEO will respect evidence from popular news outlets, think again.
Length
Advocacy letters must convey their argument clearly and concisely and use evidence effectively.
Because they are written to busy people, they are often about two single-spaced pages in length. Your advocacy letter should be about that length as well
Your stakeholders are most likely busy professionals who are accustomed to receiving information packaged in specific ways. They are not college professors, so the college research paper won’t work for them.
Thus, you need to format your final argument in a genre that helps your stakeholder process your appeal quickly and effectively. An advocacy letter is a genre that is suited to both persuasion and to efficient communication of information