Projection Types

 

Here's a quick description of the tables available with a Membership.

 

steamer_hitters_ros - This is the standard projection table for hitters, similar to what you see on Fangraphs.  Additional details on these statistics are shown in the glossary below.

steamer_hitters_ros_split - This table has three lines for each hitter: an "overall" line as well as "vL" and "vR" lines showing how we expect this hitter to perform against left-handed and right-handed pitching.  Look at the "split" column to know which projection you are looking at.

steamer_hitters_ros_multi_split - This table has a whopping six lines for each hitter.  For each split ("overall"/"vL"/"vR" as described above) there is a park-adjusted (pn=1) and park-neutral (pn=0) projection.  In this table, you need to look at both "split" and "pn" to know which projection you are viewing.

steamer_pitchers_ros - This is the standard projection file for hitters, similar to what you see on Fangraphs.  Additional details on these statistics are shown in the glossary below.

steamer_pitchers_ros_split - This table has two lines for each pitcher: A park-adjusted line (pn=0) which is a projection based on the park in which this pitcher is expected to pitch and the quality of the defense he is expected to have backing him up and a park-neutral (pn=1) line which also assumes average defense.

steamer_pitchers_opp_batter_splits - This table has six lines for each pitcher and shows their projected platoon splits (where the column split is either "overall", "vL" or "vR") in both a park-adjusted (pn=0) and park-neutral (pn=0) setting.

 

Glossary

steamerid: These are the same numbers as those shown in the URLs of Fangraphs player pages.

mlbamid: These are the same numbers as those shown in the URLs of MLB player pages and are useful for matching projections up with other projections or statistics.

pn: 0, 1 or 2 (for pitchers). 

• pn = 0 is a standard park-adjusted projection.  These are the results we actually expect given each pitcher's home park and defense.
• pn = 1 is a context-neutral projection.  This is how we would expect the pitcher to perform in a neutral park with an average defense.
• pn = 2 is a park-neutral but defense dependent projection.  This is how we would expect the pitcher to perform in a neutral park given his real-life defense (including his catchers).

split: vL, vR or overall.  This tells you whether the projection is for just one platoon split ("vL" is against lefties, for instance) or an overall projection which is the same as the "vL" and "vR" lines combined.

 

Pitcher Projections

role: SP or RP for a pitcher's projection as a starting pitcher or as a reliever.  

FIP: Fielding Independent Pitching

pnFIP: Park Neutral Fielding Independent Pitching.

LOB%: Left on Base Percentage

ERA-: ERA as a percentage of League ERA

BasicPF: The Runs/Game park factor used in this pitching projection.

SIERA: Skill-Interactive ERA

catcherframingruns: The framing runs projected for catcher's during the innings projected.

RAA9: Runs Above Average per 9 Innings

WAA9: Wins Above Average per 9 Innings

WAR9: Wins Above Replacement per 9 Innings

 

Batter Projections

p1-p9: The proportion of plate appearances projected in each lineup spot.

gC, g1B, g2B... : The number of games projected at each position.

posadj: Positional Adjustment  

wSB: Weighted Stolen Base Runs

UBR: Ultimate Base Running

BaseRunning: BsR (UBR + wSB)

reliability: Similar to Marcel's reliability.  This ranges between 0 and 1 and is higher for players with more historical playing.  1 - reliability is the amount of regression towards the mean.

ReplacementRuns: Replacement Level Runs

DEF_adj: A combination of Fielding Runs and Positional Adjustment

wRAA: Weighted Runs Above Average

frWAR: Framing Wins above Replacement (for catchers)

 

APIs 

The following links provide samples of Steamer APIs.

https://www.fangraphs.com/api/steamer/pitching
https://www.fangraphs.com/api/steamer/batting
https://www.fangraphs.com/api/steamer/pitching-splits
https://www.fangraphs.com/api/steamer/batting-splits
https://www.fangraphs.com/api/steamer/pitching-opp-splits