1. Rhetoric in professional communication

2. Rhetoric is the art of persuasion through effective oral and written communication.
Effective communication combines the attention to the audience, the logic of the argument, and the author’s or speaker’s credibility. All of these elements must work together for the goals of communication to be reached.
Authors or speakers must demonstrate credibility through their own knowledge and through the use and acknowledgement of others’ work on the subject.
The logic of the communication includes how argument is constructed and the evidence used to support the author’s claims.
The audience’s point of view and values and the author’s ability to write with those things in mind also influence the effectiveness of the communication.

3. credibility Acceptable standards Thorough, concise
Support with data and professional sources
In professional communication, the author demonstrates credibility by using accepted standards, thoroughly but concisely providing information, and supporting claims and findings with empirical data and the prior experience of other professionals.
Acceptable standards are set by professional organizations such as the IEEE [I triple E] or the APA, by companies themselves, or even in individual work groups. These standards rule how a document is written, organized, and published.
Being thorough about information not only shows how knowledgeable the author is, but it also provides the audience with all the necessary information to make an informed decision. In a business setting this information must also be written as concisely as possible.
Finally, the information the author imparts must be supported by data and/or professional sources. If you are writing a report about how a certain part or procedure works and you want to recommend it, you will need to convince your audience of through empirical data or referring to other professionals who have experience with the part or procedure. Professional sources can be academic, governmental, or trade publications. They are rarely news and never hobbyist or lay-person websites such as howstuffworks.com or Wikipedia.

4. audience Accepted standards Informational needs Interests or values
Professional communication is heavily audience-centered. Who you are writing for will determine much about how you write.
Consider the audience’s accepted standards. If you’re writing for other members of the IEEE, they will expect the conventional standards.
Consider the audience’s informational needs. If you’re writing for other engineers, the most technical information is important. If you’re writing for a company’s administration or for investors, they don’t necessarily need the technical specifications or processes.
Consider the audience’s interests or values. A technical audience might prefer objective language and very specific information. Administrators might prefer to focus on budgetary issues or how whatever you’re proposing or informing about will affect the company overall. Customers have different needs and values as well that you would have to address if you are writing for them.
While the author’s purpose is to inform, instruct, or influence, the audience’s purpose is to decide, to learn, or to act. In order to persuade them to make a decision, enlist their support, change their behavior, or to accept your proposal, you need to communicate in a way that is useful and acceptable to them. Without consideration for the audience, even the best idea will not be heard.

5. Supporting claims with credible evidence through logical reasoning
Empirical data
Expert testimony
Examples
Whatever claims you make in your professional writing, you must support them with evidence connected together through logical reasoning. The amount and type of evidence is dependent on the audience’s needs and expectations. Some common types of evidence for technical communication are empirical data, expert testimony, and examples.
Here is a situation that illustrates how claims supported by evidence help an author reach the communicative goal of persuading the audience.
After working with a particular piece of equipment, you want to use Procedure B instead of Procedure A for installation and maintenance, but in order to do that you have to have your supervisor’s approval, your colleagues’ respect and understanding, and the customer’s approval since it will affect the cost. Procedure A is traditional and currently the most common method. Procedure B is a new idea; it takes slightly longer and costs just a little bit more, but it is more effective in the long run.
Since your colleagues do the same work, you convince them that Procedure B is better because it will require less maintenance in the future even though it adds to their workload during installation, freeing them up to focus on other work later and not to have to repeat the work they have been doing.
Your supervisor doesn’t have time to hear a lengthy explanation of the new process and why it’s better. He just wants the facts and the bottom line. You explain, as concisely as possible, how the benefits (stronger installation, less maintenance, longevity) outweigh the disadvantages (longer installation process, which means more wait time for the customer and more pay for the employees for their extra hours) using the testimony from your colleagues and a report you read in the Journal of Professional Installation as credible sources to help support your argument.
The customer has to be convinced that the longer wait and the higher cost are better than the alternative of faster and cheaper in the short run, because it makes the equipment more reliable in the long run. The supervisor’s credibility as experienced and knowledgeable will help you here. You may also have to provide empirical data such or the findings from that article you read.

6. Credibility Audience Argument
As you can see, successfully persuading your audience requires writing for the audience’s needs, values, and expectations, exhibiting credibility through knowledge of information and standards, and supporting your claims with useful and acceptable evidence presented logically.