Every derived figure on this site has a documented method, stated assumptions, known limitations and a version. When a method changes, history keeps the version that produced it — nothing is silently rewritten.
Expected move
How the ± range is read from option prices.
Probability estimates
The model behind 'probability of finishing above / below'.
IV30 and volatility metrics
Constant 30-day implied volatility, realized volatility, percentiles, skew.
Historical accountability database
Snapshots recorded before outcomes are known, never rewritten.
Earnings moves
How implied and realized earnings moves are measured.
Data sources & pipeline
Where every number comes from and how fresh it is.
Principles
- Market-implied, not predicted. Expected moves and probabilities are readings of current option prices under stated models — they are estimates, and outcomes regularly land outside them.
- No invented data. A missing value shows a dash and the reason. Historical records begin the day this site started recording them.
- Append-only history. Snapshots are written before outcomes are known and never modified afterward.
- No advice, by design. Rankings are objective metrics with objective names; the product never says what anyone should buy or sell, and an automated language check enforces that before every release.