# How to Read These Graphs

## Runs Scored and Allowed

This graph highlights each team's runs scored and allowed per game, adjusted for park factors. Teams on the right side of the graph have strong offenses; teams on the top of the graph have strong defenses (pitching and fielding).

The three isobars (dotted lines) represent winning percentages of .400, .500 and .600. Teams can be grouped according to their position (above, below or in between) relative to the isobars. Teams in the upper left of each group have stronger defenses, while teams in the lower right have stronger offenses.

Though runs scored and allowed are closely related to wins and losses, they are not perfect predictors of wins. The table to the right of some of the graphs lists the number of wins each team has achieved above or below the number of wins that would be expected, based on actual runs scored and allowed. Teams with positive numbers in this table have more wins than their position on the graph would indicate. And vice versa for teams with negative numbers.

## OBP and ISO by Team

This graph lays out the two basic offensive components of each team: getting on base and moving runners around. Teams to the right have higher On Base Percentages, and teams toward the top have more power. In this case, power is measured by a statistic called Isolated Power (ISO), which is slugging percentage minus batting average. This is the best measure of which teams hit the most extra base hits.

The two dotted lines represent the league average for each category. The teams in the upper right quadrant are the best offensive teams, and the teams in the lower left quadrant are the worst.

Although these two components are highly related to actual runs scored, they are not perfect predictors. The table to the right of some of the graphs lists the number of runs scored per game above or below the predicted number of runs scored. Teams with positive numbers in this table are actually scoring more runs than their position on the graph would indicate. And vice versa for teams with negative numbers.

This table is created using David Smyth's Base Runs formula. There is a link to his formula in the "Dirty Details" section.

## Pitching and Fielding

This graph highlights the two key aspects of defense: pitching and fielding. The horizontal axis plots Tangotiger's Fielding Independent Runs (FIP), which are a function of the things a pitcher controls: strikeouts, walks and home runs. Teams to the right have better pitching.

The vertical axis plots the Defense Efficiency Ratio (DER) of each team. This is the percent of batted balls in play that are succcessfully converted into outs by the fielders. It basically covers most of the batted-ball events not included in FIP. A high team DER is a function of both good pitching (getting the batters to hit balls directly at fielders, for instance) and fielding (successfully converting fieldable balls into outs). This data is adjusted for the home park (See the Dirty Details for more info).

The circles represent the quality of the teams' fielding. The circle sizes are proportional to the percent of fieldable balls successfully converted into out by the fielders. It is based on work by David Pinto at Basball Musings.

For example, a team in the upper right quadrant will have demonstrated good pitching and will have successfully converted batted balls into outs. If the cricle size is also large, their fielders played the key role in their high DER; if it's small, the pitchers played the key role in their high DER.