What makes an effective argument

What kind of evidence should you include to strenghten your arguments?

There are 3 rules to keep in mind:

1.
Use real and specific data wherever possible. (try to avoid general and abstract)

2.
Include evidence of many different types including evidence against your proposal

3.
Pay particular attention to what is new and different in your information

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If you don't have much time to read further you can just watch these short videos:

Vladimir Kovar arguing against corruption on TV
Notice his start button, specific examples and strategic ending

 

Perhaps, now, you want to read on ...

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REAL AND SPECIFIC DATA

People prefer specific facts, information about real situations and actual photographs rather then ilustrations. So don't just say 75% of our suppliers prefer this arrangement, but also provide one or two quotes from real suppliers saying what they like about it.

If your information is conceptual, support it with some data as an example.

Don't say: "This is the concept of how we are going to reduce costs". You can say: "This is what happened to costs in our plant in Belgium, when they introduced the proposed measures"


DIFFERENT TYPES OF EVIDENCE

When you are making you case, make sure that you include many different types of evidence and arguments:

Quantitative and Qualitative Data
don't use just numbers, give us some examples, illustrations, diagrams, photographs or real product examples

Multiple Arguments
The more evidence you include, the better. This is true whether or not your audience is concerned about the issue which is discussed. More arguments are more effective and they give the correct impression of a strong case being made.

Casual arguments
Casual argument shows how one thing leads to another. People are more willing to be convinced when they understand that something will be successful, but also why. 

Don't just say: "Our research shows that serif fonts are more readable (Times New Roman). That't because the little serifs allow to process the letters more quickly"

Evidence about the problem
Evidence against your recommendation

It may sound counter intuitive, but you should also include evience that supports competing, alternative solutions and evidence against your recommendation. 

Why?

You will be more credible with the audience because they see that you are taking comprehensive view, not just selecting information in your favour.


NEW AND DIFFERENT INFORMATION

Whenever possible include information that is new and different. Especially if you are presenting project update or research study. 

In this case you usually have too much information and you need to leave something out.
Don't repeat what people know already, or what they can simply read.


WHAT TO LEAVE OUT

Don't make your audience feel guilty or irritated. 
You will not be able to persuade them.