"If he's such a good hitter, why doesn't he hit better?" - Michael Lewis, Moneyball
"Truthiness" is not truth. Math may or may not be the queen of subjects, but helps find truth amidst a world of distortion.
Cognitive biases are our internal 'wiring' errors. They mislead us via the 'eyeball test' as "I know what I see." Here are just a few and how they apply to sport and coaching.
Endowment Bias. We "overvalue" what is ours, whether it's a coffee mug, our residence, or the athletic performance of our favorite team or child. It's built-in lack of objectivity. It's "My dog's better than your dog" and "my team deserves better regard." Maybe it's why some people write columns about their team.
"My players," the players I coached, get overrated in my mind. Some earn 'external validation' such as college scholarships, All-State, or All-Scholastic status. A coach asked me why I was hyping a young player. He coached her for three days and said, "best prospect to ever come out of Melrose."
Anchoring. Anchoring keeps us fixated on the first information we obtain. "She was a first round draft choice." Those high draft choices and bonus babies keep getting a chance to prove themselves. If I compare a player (comp) to another player, another coach may see her more positively. "She could be another Hannah Brickley."
A team's performance depends on talent. Is a player a lottery pick, a first round draft choice, second rounder, or street free agent? You win with lottery picks and first rounders and they're hard to come by.
Sample size. More data produces more reliability. Flip a coin ten times and you can get seven heads and three tails. Flip it 10,000 and you won't get seventy percent, unless there's 'crooked dice' in play.
I asked a local coach how long it took for him to know a certain player would be excellent. "About five seconds." Sometimes you know.
Confirmation bias. Confirmation bias has us read and study what supports our beliefs. "How good is our team?" The playoffs help define that.
Fundamental attribution error. FAE has us judge others' actions according to character and ours according to circumstance. "He was speeding. What a thoughtless driver!" Was he rushing to get a loved one to the hospital or is he, in fact, a road menace?
Did Joe take those shots because 'he's a hun' or the coach told him to shoot more?
Recognizing cognitive bias can help us make better decisions. "Seek understanding not validation."
For more on cognitive biases, here is a reference.