Statistically-inclined teams use analysis not just to value players but to dictate strategy (less sacrifice bunting, less base stealing), which lets the front office intrude on the manager's traditional turf, leaving the manager a more recessive figure whose diminished authority is visible to players—making his people-management job harder and less pleasant.

Fielding percentage is a poor measure of defensive ability because, as Bill James showed, to commit an error a player must first reach the ball; the easiest way to avoid errors is simply not to get to the ball, so stressing errors perversely rewards limited range—which is why the A's built a new accounting of the game to measure range directly.

Beane granted Lewis access because he saw no downside—most of the A's knowledge was freely available off the web, so secrecy was never the protection; Beane believed baseball management was so set in its ways that no book would change how rival front offices thought.

The Oakland A's used statistical analysis to the near-exclusion of traditional scouting because, operating with far less money than competitors, Billy Beane realized that without a better way to assemble a team he was doomed to lose—necessity forced the innovation, not profit-seeking ideology.

The left tackle commands premium pay because he protects the blindside of a right-handed quarterback dropping back to pass; a quarterback hit from behind is more likely to be injured and to fumble, and since the passing game has grown steadily more important than the running game, protecting the blindside became the linchpin of the offense in a way the right tackle is not.

Professional athletic careers have huge arbitrary components beyond injury luck: a productive player like Scott Hatteberg, picked off the refuse heap, would have been out of baseball entirely had the A's not recognized that his ability to get on base was valuable.

The New England Patriots succeed by treating players strategically like commodities—letting glory players go once they become overvalued stars and replacing them with cheap substitutes, going for it on fourth down more than other coaches, and reportedly valuing roster depth (the 38th–51st players) because injuries accumulate over a season.

The persistence of inefficiency in industries with low barriers to entry (movies, Wall Street) suggests, as behavioral economists would argue, that human-judgment biases produce inefficiency even in highly competitive businesses no matter how competitive they are.

Like Chilean professional soccer clubs that openly carry university names without pretense, American football factories such as Oklahoma and Alabama already are professional teams; abandoning the amateurism pretense and openly paying players would not damage fan identification, since cities identify with teams like the Raiders regardless.

The offensive line is actually asymmetric: because most running backs run right, the right side gets an extra blocker, and because the best pass rushers line up across from the left tackle, the right tackle faces less ferocious threats—so the asymmetry compounds the left tackle's higher value.

The student-athlete romance forces a costly, harmful fiction: colleges build infrastructure to pretend unqualified football players are normal students (taking tests and homework for them), players can graduate without learning to read, and those not canny enough to game the system are weeded out before college, leaving them no easy path to the pros except a sham education.

The change in baseball came not from front offices reading Moneyball and converting, but from team owners—prompted by Wall Street friends who read Lewis's other books—pressuring their general managers; the pressure to adopt the new methods flowed top-down from ownership feeling let down by management.

The A's were able to innovate radically precisely because they operated in Oakland where there was effectively no media scrutiny; the same innovation attempted in a high-media market like Boston would have been crucified before it could prove itself, making low-scrutiny environments a structural advantage for experimentation.

On-base percentage was empirically undervalued before 2002, but after Moneyball was published the market corrected the inefficiency through competition—by some accounts OBP became overvalued—forcing Beane to seek new arbitrage opportunities such as superior measurement of defensive ability.

Defensive ability metrics are a more durable arbitrage edge than on-base percentage because they are harder to copy and more proprietary—reliable defensive measurement is more of an art, requires more time and energy, and yields a smaller per-player benefit, so the market will be slower to catch up.

On-base percentage—which includes the ability to draw walks—was the single statistic most closely correlated with scoring runs, yet it was undervalued because historically drawing walks was seen as something pitchers did rather than a hitter's skill; the A's exploited this by acquiring players with high OBP but ordinary batting averages and little power, since conventionally attractive stats were already properly priced.

A baseball manager's job is far easier than a football coach's because it is mostly people-management rather than strategic complexity—an untrained person installed as Yankees manager might not lose many more games, whereas an untrained head coach of the Patriots would be a disaster because he genuinely would not know what he was doing.

Michael Oher's transformation—from an illiterate, effectively homeless 16-year-old whom society had written off into a 3.9-GPA Chancellor's-List student and projected first-round NFL draft pick—demonstrates that human value is determined by context and circumstance rather than innate character flaw; removing people from pathological situations and placing them in healthy ones reveals how quickly they adapt.

If a conspicuously gifted athlete like Oher—6'5", 350 pounds with all the physical gifts of an NFL left tackle—could have his value completely ignored by the world at 15, it raises the question whose value cannot be ignored; he is therefore a parable for the systematic undervaluation of human resources.

Free agency caused the NFL left tackle's relative pay to jump dramatically—from being indistinguishable from and below other offensive linemen to the second-highest-paid player on the field after the quarterback—because when forced to make explicit valuation decisions, teams reckoned this off-camera position was that important.