The following definitions and explanations are quoted or adapted from the following texts:

• The Structure of Argument
  by Annette T. Rottenberg
  
  
• The Little, Brown Handbook
  by H. Ramsey Fowler and Jane Aaron

Evaluation of Evidence

• Facts are statements whose truth can be verified by observation or research.
  
  
• Statistics are facts employing numbers.
  
  
• Examples are specific instances of the point being made.

Questions to ask about all types of evidence.

1. Is the evidence up to date?
   
   
2. Is the evidence sufficient?
   
   
3. Is the evidence relevant?

Evaluation of Examples (distinguish between real and hypothetical examples)

1. Are the examples representative?
   
   
2. Are the examples consistent with the experience of the audience?

Evaluation of Statistics

1. Do the statistics come from trustworthy sources?
   
   
2. Are the terms clearly defined?
   
   
3. Are the comparisons between comparable things?
   
   
4. Has any significant information been omitted?

Expert Opinion
An expert opinion is the judgment formed by an authority after he or she has examined the evidence.

Evaluation of Expert Opinion (Authorities)

1. Is the source of the opinion qualified to give an opinion on the subject?
   
   
2. Is the source biased?
   
   
3. Has the source bolstered the claim with sufficient and appropriate evidence?