GUIDES · BETSLIP DOCTOR
What should I check before comparing WAR figures from different providers?
Check who calculated each WAR value and how. WAR is an estimate relative to replacement level, not one universally fixed formula; two providers can use different inputs and still follow the same broad framework.
For Bettors and cappers learning to read baseball records · Updated
Name the provider and player role
MLB identifies FanGraphs WAR as fWAR and Baseball-Reference WAR as bWAR or rWAR; it notes that methods differ, including the pitcher run measure used. FanGraphs also documents separate position-player and pitcher calculations.
A label such as WAR is incomplete without the provider and whether the value is for a position player, pitcher or combined total.
Check the method before comparing decimals
Record the source, season, method-page date, player role, fielding and baserunning components, league and park adjustments, replacement baseline and any data-coverage limits. Provider methods can change, and the same number of decimal places does not make two estimates identical.
Keep the sources side by side. Do not average, convert or “correct” one provider’s WAR into another without a method that supports that operation.
A fictional two-provider card
Hypothetical comparison for one invented player and season: Provider A reports fWAR 3.4; Provider B reports bWAR 3.1. Keep each value with its provider label, role, season and methodology link. The difference is not automatically a typo: the providers may build the estimate from different components or adjustments. These invented figures are not actual player data.
Related questions
Can I convert fWAR into bWAR with one universal adjustment?
No. There is no universal conversion established by the shared WAR label. Compare the underlying provider methods and keep their estimates identified separately.