A team's expected win rate can be estimated from runs or points scored and conceded, better than from its actual record.
James's formula estimates wins from scoring ratios and predicts next season's record better than this season's record does, because the difference between the two is mostly luck in close games. It is a regression-to-the-mean instrument disguised as a scoring model, and it transferred from baseball to basketball and football with adjusted exponents.
In practice
- A team that outperformed its scoring difference is expected to decline, and usually does.
- A manager sacked after an unlucky season is replaced by one who inherits the correction.
- Further reading
- Wikipedia
- Subject
- Sport & Performance
- Essay
- The best-measured contests there are