Era Dial
Turn a dial through baseball history and watch strikeouts, home runs and contact change, with every major rule change marked along the way.
Builds on Answers for Coach
- Coach questions
- 3
- Asked on air
- 13×
- Top question
- Q-13
Coach questions it could answer
The playbook →- How much has the ball and the home run era shifted?
Put home runs per game on the same dial so the home run era's peaks and dips line up against the rule changes and against strikeouts.
- Which recent rule changes measurably changed the game?
Mark the 2023 pitch clock, shift limits and bigger bases, and the 2026 ABS challenges, and show each stat in the seasons before and after.
- How have strikeout and two-strike contact norms changed by era?
Draw league strikeout rate and two-strike contact every season, so any comparison between eras starts from what was normal then.
Data it needs
The data lake →0 of 2 on hand; the rest arrives in phase 1, The spine.
Could use later: Every pitch, Play-by-play
The question
The hosts constantly compare players across eras and argue about whether a rule change worked. Both need the same thing first: what was normal in each season, and how sharply it moved when the rules did.
How it would work
- A dial or slider moves through the seasons; league strikeout rate, walk rate, home runs per game, batting average and stolen bases update with it.
- Rule changes sit on the timeline as markers, with before-and-after numbers a click away.
- A two-season comparison mode for era arguments.
First version
- Every season since 1901 for the counting stats, and since 2008 for pitch-level stats like two-strike contact.
- Markers for the 2023 rule changes and the 2026 ABS challenges, with the three seasons on either side.
The data
MLB Stats API season totals for league-wide rates, and Statcast and earlier pitch tracking for two-strike contact.
What it needs
- Era-consistent definitions. Some stats weren’t recorded the same way in every era, so the dial has to show where a line starts.
- Honest before-and-after. One season after a rule change also carries everything else that changed; the page should say so.
Status
An idea on the launchpad. Nothing is built yet.