In my competitive intelligence business, we constantly speak to (and read about) executives who fiercely defend what they know about their market (customers, prospects, competitors, distribution channels, features, and more), and dismissing any information or point of view that runs counter.

As you clearly stated, perspective is key to successful decisions. What entrepreneurs and executives fail to recognize is that what they know is dated. It may be a week old, a month old, a year old, or 5 years old. Therefore, unless they conduct due diligence, they don’t know if what they know is still true – or changing. Further, because new information or insights are likely to be at odds with their assumptions / beliefs, they’re easily ignored or rationalized.

As Peter Drucker stated, what you know about the external world should be 90% of your input, compared to 10% from inside your company – and that it’s reversed for most companies (acc. to Drucker.)