Methodology · vocabulary
Glossary
These fifteen terms are how Evidaxis reads the systems we track over time. Each one is a formula: it names the exact signal, window, and threshold, so any number on this site is checkable against its hash-pinned inputs in the public CC0 data. Rate of change, never size. A baseline recorded now, before the flare.
- Momentum
- The slope of a system’s public signals over time: how fast it is moving. Evidaxis scores that slope and nothing else. A repository with two million stars and a flat curve scores zero.
- Momentum Score
- A 0–100 readout that maps a system’s within-cohort axis z-scores onto a single number within a cohort, collapsed to one number. A convenience view only. Recognition is decided by the convergence gate, never by this number.
- Development velocity
- Axis 1: the least-squares slope of log(1 + weekly commits) over the trailing 26 weeks. A fast, leading signal of where active work is accelerating.
- Citation momentum
- Axis 2: the slope of log(1 + citations per year) to a system’s canonical paper (OpenAlex). A slow, confirming signal of scholarly acceleration. Three rules keep it honest: drop the partial current year, drop the birth year once four full years exist, and require at least three completed years.
- Within-cohort robust-z
- Normalization: a raw axis slope is converted to a z-score using the median and median absolute deviation of its cohort (resistant to a single outlier), so "rising" means rising relative to peers, not in absolute terms.
- Residualization
- After the robust-z, each axis is residualized against a size proxy (log stars for velocity, log total citations for citations) so that scale is removed and only relative momentum remains. This is how a small fast-mover can show more momentum than a large incumbent.
- Convergence Gate
- The recognition rule (methodology m2): a system is Rising only when its cohort has at least five members, at least two independent axes are present, and at least two are rising at once (raw slope greater than zero and within-cohort z at least one; development velocity additionally requires at least five average weekly commits). The gate only ever promotes. A system is Rising, or it is not yet, by design.
- Rising
- Status: two or more independent axes converge upward within the cohort. The full badge, and the rare one. It fires only when two separate signals agree, so a single pushed number cannot earn it.
- Watch
- Status: exactly one axis is rising; a second independent axis has not yet converged. A candidate signal, not a badge.
- Tracked
- Status: measured on two or more axes, none currently rising relative to the cohort.
- Single-axis
- Status: only one axis is available (for example, no academic paper exists), so the system cannot satisfy the two-axis convergence gate. Measured on one axis and labeled as such.
- Calibration
- Status: a mature incumbent included to anchor a cohort’s statistics. Measured but never badge-eligible: the badges go to systems on the rise.
- Cohort
- A peer set (a sub-niche within an industry) against which a system’s momentum is normalized. Membership controls the z-scoring, so a human draws the cohort line by hand.
- Snapshot
- A frozen, dated, hash-verified record of every measurement at a point in time, released under CC0. You cannot back-fill a baseline after the flare. The snapshot series is the part that compounds: a longitudinal map that no one can reconstruct from scratch later.
- Score receipt
- Three fields ride with every published number: methodology version, snapshot id, and manifest hash. With them, any score is independently checkable against its hash-pinned inputs in the public CC0 data.