How Stat Above Average works
One formula, applied identically whether you struck people out or drove them in.
A hitter's Stat Above Average (SAA) is built one season at a time. Each season, four rate stats and a fielding number are turned into z-scores — standard deviations above or below the bar for that season, measured against qualifying hitters only — then blended by weight, scaled to a 600‑plate‑appearance workload, and summed across the career. The bar is mostly the league, but tilted toward the player's own position; a below-average season is dampened before it's added in. Both adjustments are explained under the formula. The ranking number is a JAWS-style 50/50 average of that career total and the sum of the player's seven best individual seasons, so a long steady career and a short brilliant one can both build a real case.
A pitcher's SAA works the same way, minus the peak adjustment: five z-scored rate stats per season (ERA and WHIP flipped, so beating the league counts as positive), blended by weight, scaled to a 200‑inning workload, and summed across every qualifying season. There is no best-seven bonus — a pitcher's number is the career total only.
Every comparison is to the player's own contemporaries in the exact seasons he played — a 1927 season is judged against 1927, a 2024 season against 2024. A career that spans eras gets a benchmark blended across those years. Nothing is measured against a fixed all-time standard or a replacement‑level constant. The weights are deliberately tilted toward contact, power, and run prevention: a walks-only bat or a pure basestealer could otherwise ride a single category past a complete player.
The bar bends toward your position. A good-hitting shortstop still looks ordinary next to a league full of first basemen and corner outfielders, which for years buried the great up-the-middle players — the Ripkens, the Larkins, the Benches — a hundred spots too low. So the four bat-and-legs categories aren't scored against the whole league anymore. Each is measured against a bar set 60% of the way from the league average toward the average for the player's own position (shortstop, second base, catcher, and so on) that season. Defense was always judged this way. Held fully to position it would swing too far the other way — telling the formula a no-hit shortstop is "average" and floating good gloves with empty bats up the list — so it lands at 60%.
Hanging on doesn't erase what came before. Because every season is scored against the league, a below-average year comes out negative and eats into the career total — which quietly penalizes a great player for sticking around a few years past his prime. Those sub-average seasons still count, but at 40% weight in the career total. The peak half of the formula — the seven best seasons — never includes them anyway.
Glossary
Every abbreviation you'll run into on the lists, the cards, and the Stats pages.
The five hitting inputs
- AVG — Batting average
- Hits divided by at‑bats. The oldest measure of pure contact.
- ISO — Isolated power
- Slugging percentage minus batting average: extra bases per at‑bat, with singles stripped out. A hitter with nothing but singles has an ISO of .000; prime Babe Ruth sat around .350.
- Defense (Fielding Runs)
- Baseball‑Reference's Fielding Runs for the season — range in the field, catcher defense (throwing, framing, blocking), small good‑play adjustments, and the positional adjustment that values a shortstop's spot above a first baseman's and docks a designated hitter for not taking one. Divided by games and scored against the league like the other four. This is the one SAA input that isn't a plain rate stat: fielding has no clean box‑score number, so SAA borrows a real one rather than build a worse substitute. Earlier editions used a home‑made putout‑and‑assist range figure that couldn't see catcher defense at all.
- Walk rate (BB)
- Bases on balls as a share of plate appearances — how often a hitter reaches base without putting the ball in play.
- Steal rate (SB)
- Net stolen‑base value per plate appearance: steals credited, caught‑stealing charged at a heavier penalty. Weighted lightly on purpose.
The five pitching inputs
- ERA — Earned run average
- Earned runs allowed per nine innings. Lower is better, so the z‑score is flipped before it's blended.
- WHIP — Walks and hits per inning pitched
- Baserunners allowed per inning, walks plus hits. Also flipped — fewer is better.
- K/9 — Strikeouts per nine innings
- The one bat‑missing skill that shows up on every stat sheet, in any era.
- Win% — Winning percentage
- Wins divided by decisions (wins plus losses). It leans on the team around the pitcher, so it carries a modest weight.
- SV — Saves
- Games finished protecting a lead, per the official rule. Weighted lightest of the five: it depends heavily on how a manager chooses to use a pitcher.
Other batting stats on the site
- POS — Position
- The fielding position (or positions) a hitter is most associated with, on the Hitters list. It's every position — including DH, for games with no position at all — covering at least 20% of his career games, most‑played first, computed from every game of his career, not just qualifying seasons. A true utility player can carry more than one: Pete Rose shows OF/1B. This is separate from SAA's defensive score, which uses Baseball‑Reference's Fielding Runs and factors into the ranking; POS is purely descriptive and never affects a player's rank.
- OBP — On‑base percentage
- Times reached base (hits + walks + hit‑by‑pitch) divided by plate appearances.
- SLG — Slugging percentage
- Total bases divided by at‑bats — a double counts 2, a home run 4.
- OPS — On‑base plus slugging
- OBP + SLG. A quick catch‑all for offensive value; .900 and up is star level.
- OPS+ — Adjusted OPS
- OPS restated so 100 is league average and each point above is one percent better, adjusted for ballpark. 150 means 50% better than league.
- PA — Plate appearances
- Every trip to the plate, walks and sacrifices included. SAA scales each hitting season to 600 PA.
- R, RBI, HR, H, 2B, 3B, SB, BB, SO
- Runs, runs batted in, home runs, hits, doubles, triples, stolen bases, walks, strikeouts — raw season and career totals, no adjustment.
Other pitching stats on the site
- IP — Innings pitched
- Shown in the traditional thirds notation: 200.1 is 200 innings and one out, 200.2 is two outs. SAA scales each pitching season to 200 IP.
- ERA+ — Adjusted ERA
- ERA restated to a 100‑is‑average, park‑adjusted scale where higher is better — the inverse direction of raw ERA.
- W, L, G, GS, CG, SHO
- Wins, losses, games, games started, complete games, shutouts.
- H, ER, HR, BB, SO (allowed)
- Hits, earned runs, home runs, walks, and strikeouts a pitcher gave up.
Methodology terms
- z‑score
- How far a number sits from the average, measured in standard deviations. A z of +1 is one standard deviation better than that season's qualifying players; +2 is rare air. SAA blends z‑scores, not raw stats, so separating yourself in a tightly bunched category counts for more than in one where the league is spread all over.
- “vs league” / league‑relative
- Every rate input is scored against the average of the same season, never a fixed all‑time bar. This is the core difference from career‑counting totals and from WAR's replacement level. (The defensive input starts from Baseball‑Reference's Fielding Runs, then that too is scored against the season's league.)
- “vs position” / position‑relative
- The bar an input is scored against is nudged toward the average for the player's own fielding position that season, so a shortstop's bat is measured mostly against other shortstops. Batting average, isolated power, walk rate and steal rate are 60% of the way there, 40% still whole‑league. Defense is inherently position‑relative — a shortstop's Fielding Runs already compare him only to other shortstops, plus the positional adjustment for playing the harder spot.
- Decline‑season weighting
- A qualifying season that grades out below average scores negative, which subtracts from the career total. Those negative seasons are cut to 40% weight before they're added in, so a long tail of past‑prime years dings a great career without gutting it. The peak component is untouched.
- Qualifying season
- A season that counts toward SAA: 200+ plate appearances for a hitter, 40+ innings for a pitcher. Below the line, a season doesn't move the number.
- Two‑way players
- Hitters and pitchers are scored as two entirely separate pools, each with its own career‑volume floor to even qualify — 5,000+ PA for hitters, 1,000+ IP for pitchers — and there's no mechanism to combine value from both roles into one ranking. A player who genuinely splits his career between them can miss both floors on his own even with a historic combined career. Shohei Ohtani is the case: as of this edition he sits around 4,300 career PA and 530 career IP, short of each bar independently, so he appears on neither list. That's a structural gap in a formula built for one role at a time — not a judgment on him.
- Peak / best‑seven
- For hitters, the final SAA is a 50/50 average of the career total and the sum of the seven best individual seasons — the same idea as Baseball‑Reference's JAWS. It stops a compiler with no great years from outranking a shorter‑career great. Pitchers get no peak component.
- WAR / bWAR
- Wins Above Replacement, the mainstream all‑in‑one value stat. “bWAR” is Baseball‑Reference's version, the one quoted on this site. See Why not WAR? below.
- Replacement level
- The baseline WAR measures against: what a team could get essentially for free from the minor leagues or the waiver wire. SAA has no equivalent — it compares to the real league, not a hypothetical floor.
- NeL
- A flag on the lists marking a player whose SAA draws on Negro Leagues seasons — now part of the official record and scored exactly the same way.
- Cooperstown / HOF
- The Baseball Hall of Fame in Cooperstown, New York, and its membership, which is decided by vote. The HOF column on each list shows who is already in.
Why not WAR?
Wins Above Replacement measures every player against one universal "replacement level" — a theoretical bench player, calibrated once from decades of injury-substitution data and then applied identically to a dead-ball-era outfielder and a modern closer. It's the industry standard for good reason, but that one number was never derived for either of them specifically.
Stat Above Average measures every player against their own competition instead — the actual league average, in the actual years and at the actual position they played, blended across whichever eras their career spans.
No replacement level. No runs-to-wins conversion. No linear-weight run values turning a double into a decimal. Just each player's rate stats, held up against the players who were actually on the field around them — with one exception: fielding has no clean rate stat, so the defensive input starts from Baseball-Reference's Fielding Runs before being scored against the league like everything else.
Different question, different answer — but not a wildly different one. The Credibility page lays SAA next to WAR, WAA, and JAWS across the whole pool: where they line up, where they part ways, and the reason behind every gap.