YagoonaraWAR Calculation Guide (eWAR)
How Yagoonara calculates estimated WAR (eWAR).
What is WAR?
WAR (Wins Above Replacement)measures a player's total contribution to their team in terms of wins compared to a replacement-level player.
For example, a player with 5.0 WAR contributed approximately 5 more wins than a replacement-level player would have.
WAR Interpretation
bWAR vs fWAR — Same WAR, Different Philosophy
WAR is not one formula. The same concept has multiple versionswith different methodologies. The two most prominent are Baseball Reference's bWAR and FanGraphs' fWAR.
Key difference in one line
bWAR = based on actual results · fWAR = based on pitcher skill/process
The biggest gap is in pitching
| Aspect | bWAR (B-Reference) | fWAR (FanGraphs) |
|---|---|---|
| Pitcher metric | RA9 (actual runs) | FIP (K, BB, HR) |
| Defense influence | Included | Removed |
| Luck (BABIP etc.) | Included | Removed |
| Defense metric | DRS / TotalZone | UZR |
| Philosophy | "How well did they perform?" | "How skilled are they?" |
| Strength | Real-world results, MVP debate | Predictive, analysis |
Real example
The same pitcher in the same season can have bWAR 8.4 vs fWAR 4.1 — nearly double the difference. Pitchers on teams with great defense get inflated bWAR, and vice versa.
For batters, the gap is smaller
Both use wOBA-based batting evaluation, so the overall framework is similar. Differences come mainly from defensive metrics (fWAR → UZR, bWAR → DRS); the more defensive value a player has, the larger the gap between the two.
Which one is correct?
Neither is "right." They serve different purposes.
bWAR is useful for
- - MVP voting and award debates
- - Actual team win contribution
- - "How well did they do this season?"
fWAR is useful for
- - Trade and contract value analysis
- - Future performance prediction
- - "What is the player's true skill level?"
Yagoonara's eWAR follows the fWAR approach
eWAR uses FIP-based pitching + wOBA-based batting, making it an fWAR-family metric. The detailed RA9 data needed for bWAR is not available in KBO, and FIP better reflects a pitcher's pure ability.
eWAR — Yagoonara's Estimated WAR
Yagoonara's eWAR (estimated WAR) is based on the FanGraphs fWAR methodology, adapted for the KBO data environment.
| Component | fWAR | eWAR | Accuracy |
|---|---|---|---|
| Batting (wRAA) | wOBA-based | wOBA-based | ★★★★★Same |
| Baserunning | SB+advance+GDP | SB+GDP | ★★★☆☆~50% |
| Fielding | UZR (zone) | RF+errors | ★★☆☆☆~25% |
| Pitcher WAR | FIP-based | FIP-based | ★★★★★Same |
| Park Factor | Direct calc | Auto calc | ★★★★☆~80% |
Note
Even MLB calculates WAR using RF+error-based defense (TotalZone) for seasons before 2002, when zone data was unavailable. Our defensive estimate uses the same approach.
Batter eWAR Formula
1. Batting (wRAA)
Difference between player wOBA and league average, scaled by wOBA scale (1.15) and plate appearances.
2. Baserunning
3. Fielding
4. Position Adjustment (per 144G)
| C | SS | 2B | 3B | CF | LF | RF | 1B | DH |
|---|---|---|---|---|---|---|---|---|
| +9 | +5.5 | +2 | +2 | +2 | -5 | -5 | -9 | -12 |
5. Replacement / RPW
Pitcher eWAR Formula
Pitcher eWAR uses the same FIP-based calculation as fWAR.
FIP = (13×HR + 3×(BB+HBP) - 2×K) / IP + FIP_constant
FIP_constant = lgERA - lgFIP_raw
Why FIP-based?
FIP measures pitcher skill using only strikeouts, walks, and home runs. Unlike ERA, it removes defensive influence, providing a purer measure of individual contribution.
Differences from MLB — KBO Adjustments
Yagoonara's eWAR is based on the FanGraphs fWAR formula, adjusted for the KBO league environment.
FanGraphs (MLB) vs Yagoonara (KBO)
| Item | FanGraphs (MLB) | Yagoonara (KBO) | Reason |
|---|---|---|---|
| Defense metric | UZR (zone data) | RF + errors (±10 cap) | No zone data in KBO |
| Defense weight | Original (0.4~0.6) | Conservative (0.05~0.30) | RF precision limits |
| Position adj. | MLB original | ~20% reduced | KBO defense data precision |
| Batter RPW | Dynamic calc | 9.264 (fixed) | Simplified calculation |
| Pitcher RPW | Dynamic calc | 7.5 (fixed) | Fair batter-pitcher WAR comparison |
| Pitcher Replacement | ~0.03/9IP | 0.05/9IP | Approximate external WAR levels |
| Baserunning | SB+advance+GDP | SB+GDP | No advance data |
Why the differences?
KBO does not have precise defensive data like UZR (Ultimate Zone Rating).
RF (Range Factor) is based on simple putouts + assists and has low precision, so we apply conservative weights and a ±10 runs cap per position.
Position adjustments are reduced by ~20% from MLB standards to compensate for the lower precision of RF-based defensive evaluation.
Pitcher RPW is set to 7.5, separate from batters (9.264), to mitigate pitcher undervaluation in batter-pitcher WAR comparisons.
Comparison with external WAR
The same player in the same season can have different WAR values across sites.
- - Defensive evaluation method (UZR vs RF vs DRS)
- - Pitching evaluation basis (FIP vs RA9)
- - RPW and replacement level settings
- - Park factor calculation method
These differences are not "errors" but "differences in perspective."
Park Factors
Each stadium has different scoring environments. 1000 is neutral; higher means hitter-friendly, lower means pitcher-friendly.
Yagoonara auto-calculates park factors from actual game result data.
| # | Stadium | Park Factor | Type |
|---|---|---|---|
| 1 | 사직 | 1123 | Hitter-friendly |
| 2 | 문학 | 1095 | Hitter-friendly |
| 3 | 광주 | 1059 | Hitter-friendly |
| 4 | 대구 | 1031 | Neutral |
| 5 | 수원 | 1013 | Neutral |
| 6 | 한밭 | 977 | Neutral |
| 7 | 창원 | 966 | Neutral |
| 8 | 잠실 | 963 | Neutral |
| 9 | 고척 | 860 | Pitcher-friendly |
* 2024 regular season
Limitations
Defensive precision: Without zone data, fielding is estimated via RF+errors, which differs from UZR/DRS-based WAR.
Baserunning scope: Extra base taking data is unavailable; only SB runs and GDP avoidance (~50% of full BsR).
Park factor precision: Stadium RPG method has slight variance vs team home/away comparison.
Nevertheless
- - Pitcher eWAR is nearly identical to fWAR (FIP-based)
- - The core batting component is accurate (wOBA-based)
- - Properly distinguishes MVP-level vs average vs replacement players
- - Very few KBO sites provide WAR, making even estimates valuable