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"Log-5" is a method introduced by Bill James to predict the probability of victory when two teams of a given winning percentage play against each other. The formula is:

WPct = A - ( A x B ) / (A + B) - ( 2 x A x B )

Where "A" is Team A's winning percentage, and "B" is Team B's winning percentage. In the simplest terms, this formula indicates how often Team A should beat Team B.

Imagine that Team A wins 50% of its games and Team B wins 38% of its games. Inputting these percentages (as a decimal) into the formula above would yield:

WPct = 0.31/ (0.88) - (0.38) = 0.62

Or, in other words, Team A should beat Team B 62% of the time.

Permanent link to Stat of the Week: Log-5

Opinion: This Isn’t Baseball…

It has been 244 days since the last MLB game was played, when the Washington Nationals beat the Houston Astros in Game 7 of the World Series. But with the recent rule changes for a shortened 2020 season, when you turn on the TV for Opening Day in 23 days, will you really be watching baseball?

Leverage measures how important a given situation is during a game (relative to the start of the game). The start of a game is defined as a Leverage of 1.0, a neutral situation. As the game progresses, the Leverage can fluctuate based on the inning, the number of outs, the runners on base, and the difference between the two teams' runs scored so far.

Leverage is the ratio between how much a single run scored changes the expected probability of winning in the current situation and how much a run would have changed the expected probability of winning at the very beginning of the game.

For example, if a run scored in the eighth inning increases the probability of winning by 20%, while a run at the start of the game increases it by 10%, then the Leverage of the situation in the eighth inning is 20%/10% = 2.00 Leverage.

Permanent link to Stat of the Week: Leverage

APR, or Adjusted Pitching Runs, measures the number of runs a pitcher prevented as compared to a league-average pitcher in a neutral park in the same number of innings. Derived from the pitching component of linear weights, or pitching runs, APR includes an adjustment for ballparks and is based on all runs allowed, not just the earned runs.

APR = L x IP - (R/PF)

Where "L" is the league average of runs per inning and "PF" is the park factor for the pitcher's home park.

Permanent link to Stat of the Week: APR

RA, or Run Average, is the number of runs (earned and unearned) allowed by a pitcher or team per 9 innings. Considering all runs allowed by a pitcher is more desirable from a predictive standpoint because it adjusts the arbitrary format of official scoring and the attribution, the problems of reconstructing an inning to determine unearned runs, and the small number of errors presently compared to the past that would normally be seen when measuring pitcher success through just an "earned runs" method. A pitcher good at preventing earned runs tends to be good at preventing unearned runs.

Permanent link to Stat of the Week: RA

PSP is a measure designed by Nate Silver to indicate a team's success in the postseason in divisional play. PSP assigns points to playoff teams as follows:

  • 3 points for making the playoffs
  • 3 points for winning the League Division Series (LDS)
  • 4 points for winning the League Championship Series (LCS)
  • 4 points for winning the World Series
  • 1 point for each postseason win
  • -1 point for each postseason loss

The highest possible PSP is 25, for a team that sweeps through all eleven postseason games, while the lowest is 0, for a team that is swept in the first round.

Permanent link to Stat of the Week: Playoff Success Points (PSP)

The sum of a player's on-base percentage (OBP) and their slugging average (SLG). This is a quick and easy statistic for understanding a player's offensive productivity.

OPS is more closely correlated to run scoring than batting average, on-base percentage, or slugging average alone, which is why many baseball fans prefer this statistic to compare players' offensive ability.

Understand that OPS has its limitations, such as the assumption that OBP and SLG are equal. For example, a player with a .340 OBP and a .340 SLG is offensively different than a player with a .440 OBP and a .240 SLG, despite each sets adding up to an OPS of .680.

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Permanent link to Stat of the Week: OPS

Batting average is a measure of a hitter's performance, and is calculated by dividing a player's hits by their total at-bats, over a period of time. Batting averages can range from .000 (NO hits in all at-bats) and 1.000 (a hit in EVERY at-bat). In the absence of walks, reaching a base on errors, or being hit by a pitch, a hitter with a .300 batting average gets a hit 30% of the time they come to the plate. Take any batting average (.350, .105, .446) and multiply it by 100 to get the statistic as a percentage (35%, 10.5%, 44.6%).

The MLB average batting average for the 2019 season was .252, and the batting average leader of the 2019 season was Tim Anderson of the Chicago White Sox; .335 in 498 at-bats (AB).

Permanent link to Stat of the Week: Batting Average (AVG or BA)

Last week, we discussed what a Hit was. It is crucial to understand this before we dive into these conditions, as each condition is a type of hit.

A single (1B) or base hit occurs when the batter hits the ball into play and reaches 1st base safely. In order for a batter to be credited with a double (2B), the batter (now a "baserunner") must reach 1st base safely and then 2nd base safely. In order for a batter to be credited with a triple (3B) (you guessed it) they must reach 3rd base safely after touching 1st base and 2nd base.

A home run (HR) exists in two conditions:

  1. The batter hits the ball over the outfield wall in "fair territory"(area in-between the two foul poles in left and right field).
  2. The batter hits the ball into play and the runner advances all the way to home plate safely.

It is important to note that the baserunner must touch every base they're attempting to reach while the ball is in play. If they fail to do so, they must go back to that base (in reverse order), touch it, then continue to advance. If a defensive player in possession of the ball beats the runner there, the runner will be called out.

The baserunner will not be credited with any of these conditions if they reached any of these bases on an error or fielder's choice. If the baserunner attempts to reach 2nd, 3rd, or home plate after touching 1st base, but is called out at any of those bases by an umpire, the baserunner will still be credited with a hit in the official scorebook.

Permanent link to Stat of the Week: Singles (1B), Doubles (2B), Triples (3B), & Home Runs (HR)