He's not suggesting "Guess and pass it of as true".
Instead, the idea is to say "Well, I am not sure. However, If I had to guess, I'd say X" where X is your best guess. You can follow up with "If needed, I could find out for sure in {time-frame}"
Fair clarification. I don't appreciate that approach either. Just go find out what the problem is and report back. Unless someone specifically asks you to guess, you are just wasting everyone's time. And in a meeting with clients and upper management, that could add up to $$$ thousands per hour. "If I had to guess". You usually don't have to. So don't do it. Just my $0.02. Maybe other managers see it differently.
EDIT: I should clarify why this often goes badly. "If I had to guess, it's the filter in the gas line". Now everyone thinks it's a $20 problem, and they appreciate having an expert like you around to help them mentally frame the extent of the problem. When you come back with "actually the entire engine is warped and needs to be replaced", everyone is going to be disappointed. Like it or not, that disappointment is attached to you now. Trust is lost. There is almost nothing ever to be gained from guessing.
You sound like a person who has difficulty operating in an uncertain environment.
Sometimes certainty is expensive. In fact, in my experience with complex systems, it usually is. Depending on what you're uncertain about, you may need to modify the system to measure it. Resolving uncertainty can take a long time, particularly if the thing you're trying to be certain about is a rare event or cannot easily be isolated.
When certainty is hard to achieve, making probabilistic decisions sooner and falling back to more costly decisions with more expensive certainty only after those have failed, is a better general strategy, even if you're sometimes wrong. Analysis paralysis is real. Someone who always acts the way you suggest has too much fear of being wrong, IMO.
It could be warranted in other situations, where human life is on the line. I think it's not a fast enough process for most businesses though.
> You sound like a person who has difficulty operating in an uncertain environment.
Not at all. I deal with uncertainty all the time. What I don't like is people inventing answers, just so they have an answer. I think you'll find this "intolerance" increasingly as you deal with people higher and higher up in management. People's time becomes increasingly the most expensive factor by far. Let's stay focused here. That paragraph in the article is advice about what to do when "someone asks you something you don't know". I'm still firmly in the camp of a simple "I don't know, but I will find out for you." YMMV.
Instead, the idea is to say "Well, I am not sure. However, If I had to guess, I'd say X" where X is your best guess. You can follow up with "If needed, I could find out for sure in {time-frame}"