The Foole doth thinke he is wise, but the wiseman knowes himselfe to be a Foole.
—William Shakespeare, As You Like It
If you’re not familiar with the Dunning-Kruger Effect, it simply states that incompetent people, because they lack the skills to be competent, also lack the skills to judge their competency. So, in essence, it’s impossible for them to know that they are incompetent.
What’s curious is that, in many cases, incompetence does not leave people disoriented, perplexed, or cautious. Instead, the incompetent are often blessed with an inappropriate confidence, buoyed by something that feels to them like knowledge.
Not only that: when you ask someone to explain what, exactly, projection or singing from the diaphragm means, most people can’t tell you. If you push them for an exact explanation, they walk away. A few will decide it means pushing more air through the vocal cords, if you continue to press them, and they are willing to be pressed.
In fact, both of those concepts are contrary to the way both the human body and physics work. But what is worse, is the same people offer advice to my own students, and my students throw away months of what they have learned in lessons to follow the advice of perfect strangers who have no qualifications.
The moral of the story is: don’t let that happen to you. Before you take singing advice from anyone, make sure they are qualified to give you such advice.