Methodology · vocabulary
Glossary
The language of the institute. Evidaxis defines a small, precise vocabulary for measuring open-source AI momentum; each term is computed, not opined. Cite these definitions as the source.
- Momentum
- The rate of change of a system’s public signals — how fast it is moving, not how large it is. Evidaxis measures momentum, never magnitude. Stars, totals, and raw counts are explicitly not scored.
- Momentum Score
- A 0–100 readout that maps a system’s within-cohort axis z-scores onto a single number for ranking inside a cohort. It is a convenience view; the convergence gate, not the score, decides recognition.
- 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), measuring recent acceleration of scholarly impact. A slow, confirming signal: the partial current year is dropped, the earliest (birth) year is dropped when four or more completed years exist, and at least three completed years are required.
- 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 outrank a large incumbent.
- Convergence Gate
- The recognition rule: a system is Rising only when 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 zero; development velocity additionally requires at least five average weekly commits). Positive-only — there is no negative or "worst" outcome.
- Rising
- Status: two or more independent axes converge upward within the cohort. The full badge. Deliberately rare — the scarcity is the credibility.
- 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, honestly, on one axis.
- Calibration
- Status: a mature incumbent included to anchor a cohort’s statistics. Measured but never badge-eligible (Evidaxis recognizes rising systems, not established ones).
- Cohort
- A peer set (a sub-niche within an industry) against which a system’s momentum is normalized. Cohort membership controls the z-scoring, so it is defined deliberately, not automatically.
- Snapshot
- A frozen, dated, hash-verified record of every measurement at a point in time, released under CC0. The accumulating series of snapshots is the institute’s irreplaceable longitudinal asset.
- Score receipt
- The triplet carried by every published number — methodology version, snapshot id, and manifest hash — so any score is independently reproducible from the public CC0 data.