Evidence is used to support the hypothesis of the author. Before we examine the types of evidence used by Mascetti and Barber, it would be helpful to discuss briefly the different types of evidence available. The authors whose work appears in this book use the following types of evidence:

Personal experience. Evidence based on personal experience is not necessarily the most reliable form of evidence, but it is the most widely available. The problem with evidence based on personal experience is that it can be colored by subjectivity, or one's feelings, values, and biases about a particular person, place, or thing.

Published reports. This form of evidence is usually one of the more reputable types, but it is still far from perfect. Evidence from published reports can be found from a wide variety of sources—basically anything in print, from encyclopedias...