Getting the Real Facts: How Industry Analyst Reports Can Trick Readers - page 5
Start from the Beginning
The methodology of the analysts should be apparent as you read the study. In general, a study should seem reproducible given the descriptions by the authors. Many studies will even include a section on methodology. A vague or confusing description of the techniques they used to arrive at their results is not a good sign.
Survey authors should indicate who they interviewed, including position and company size. The primary questions should also be provided. Studies involving cost should break down those costs into itemized lists. After reading the study, you should have a good idea of how the authors collected and analyzed the data. If not, then nothing was proved.
Lesson: If you don't know how the authors collected and analyzed the data, you can't be sure it's valid.