Supporting materials are the difference between an opinion and a convincing argument. Supporting materials are effective only if they help to persuade the audience. The type of supporting materials that should be deployed depend on the following:
Available supporting material: Not all types of supporting materials exist for all arguments. If there is no evidence, it obviously cannot be used.
The idea being supported: If you are trying to explain that your favorite ice cream is chocolate, then scientific evidence about the molecular composition of chocolate ice cream is not as effective as personal accounts.
The type of appeal: Emotional and logical appeals tend to be supported by different types of materials. All types of supporting material can be used for emotional appeals, but providing data may not be as effective as providing anecdotes for connecting with the audience. For logical appeals, all types can again be used, though the most effective support is scientific evidence, because it is empirical and true.
The audience: Different audiences respond differently to different types of supporting evidence. It is the speaker's job to determine what supporting materials will be most comprehensible and effective.
Regardless of the type of supporting material used, they are effective only if they fulfill the speaker's burden of proof. If the supporting materials are not delivered in a way that advances that goal, they are not deployed effectively.
EXAMPLEIf you are speaking in front of a large crowd, and use a chart printed out on a sheet of paper, it doesn't really matter what the chart says. If the audience cannot see the chart, then it will not be understood or effective. The same goes for other types of supporting materials; they are only effective if they can convince the audience.
Source: Boundless. "Using Supporting Materials Effectively." Boundless Communications Boundless, 3 Mar. 2017. Retrieved 19 May. 2017 from https://www.boundless.com/communications/textbooks/boundless-communications-textbook/supporting-your-ideas-9/deploying-supporting-materials-45/using-supporting-materials-effectively-190-4188/