StatLab
← Level 3: Linear weights

Capstone: argue without ERA

Your friend says 'his ERA is 4.40, he's washed.' Win the argument using only Level 3 tools.

The Level 3 worldview in one paragraph: every event has a run price; a hitter's value is the sum of his events' prices (wOBA → wRC+); a pitcher's skill lives in the events no fielder touches (FIP). Everything else is context and noise.

The winning argument structure: lead with the adjusted, weights-correct number (wRC+ or FIP), acknowledge what it excludes, and name the gap between it and the surface stat as either luck, defense, or park — specifically, not hand-wavily.

How this stat lies to you

  • Level 3 stats are season-sized truths — they still say nothing about tonight's start.

Check yourself

1. wOBA .350 vs OBP .350 — which hitter almost certainly produced more?

2. Pitcher: 4.40 ERA, 3.10 FIP, .335 BABIP against (career .295). Your one-line verdict?

3. Why does wRC+ beat OPS+ when they disagree?