
The quality of your analysis rests on two pillars—good thinking and good evidence—and evaluating the quality of evidence can be hard to do.
In fact, taken individually or as a body, evidence is likely to be incomplete, inconclusive, ambiguous, dissonant, and not perfectly credible (for a discussion, see Strategic Thinking, pp. 97–98).
Let’s focus on that last point: Not all evidence is equally trustworthy. You should give more weight to higher-quality evidence. And, yes, expert opinion is the least trustworthy type. Here’s a shorthand to help you stay afloat—a downloadable graphic that you can print out and keep handy.