Validation
A preliminary, concurrent association between B-index scores and documented annual retention for 14 platforms — reported with the defects of the cohort stated beside every figure, and without a claim that it validates the formula.
BHI score vs. annual retention
B-index vs. the retention figure recorded for each of the 14 platforms of paper §7.4 (SEC filings, earnings calls, CIRP, Antenna, industry reports). Hollow points are rows whose value is asserted rather than measured, is not a retention rate, or belongs to an object this index does not score. Dashed line is the OLS fit on all 14.
What this cohort shows, and what it cannot
Retention is positively associated with B in this cohort. The association is concurrent — the retention periods precede or coincide with the scores — so it is not a prediction, and no prospective test has been run. A monotone “retention floor” does not hold: in 16 of 88 comparable platform pairs the higher-B platform has the lower retention (Spotify, B = 2.31, retains 96.5% against Apple’s 89% at B = 4.60).
The cohort does not distinguish the full formula from simpler forms. On the same 14 objects and the same outcome, the escape half of the model alone gives ρ = 0.87 and the single parameter portability gives ρ = 0.87, against ρ = 0.79 for B; every paired difference between these correlations includes zero at this sample size. No incremental validity of the formula’s complexity, and no predictive validity, has been demonstrated. This cohort is a preliminary external-association check, not evidence for the formula.
Reference cohort · n = 14
The 14 platforms of paper §7.4, with the basis of each retention value. The paper’s figure is reproducible from this table; the “measured rates only” figure above excludes the rows marked asserted, non-retention or mismatched.
| Platform | Sector | BHI · V3.1 | Retention (%) | Source | Basis |
|---|---|---|---|---|---|
| Synopsys/Cadence (EDA Duopoly) | infra | 13.50 | 99.0% | Industry reports | asserted, not a measured rate — Period recorded as "Structural"; a characterisation of the market, not a measured annual rate. |
| TSMC | tech | 12.28 | 99.0% | TSMC annual report | estimated rate (medium source quality) |
| Visa | fintech | 8.82 | 99.9% | Visa 10-K filing | asserted, not a measured rate — "Zero voluntary network departures" coded as 99.9%. |
| Amazon | tech | 8.40 | 95.0% | CIRP consumer survey | retention of an object this index does not score — The figure is Amazon Prime’s annual renewal rate; the scored row is the Amazon ecosystem, and no Prime row exists. |
| NVIDIA (CUDA) | tech | 8.29 | 98.0% | CUDA developer survey | not a retention metric — The underlying metric is AI-framework share (~92%), stored as 98; it is not a retention rate. |
| Bloomberg Terminal | banks | 7.21 | 96.0% | Bloomberg LP reports | estimated rate (medium source quality) — "<5% annual churn estimated". |
| SWIFT | banks | 6.78 | 99.9% | SWIFT annual review | asserted, not a measured rate — "Zero voluntary exits since 1973" coded as 99.9%. |
| Nubank | fintech | 5.21 | 94.0% | Nubank earnings | documented annual rate |
| Salesforce | saas | 4.76 | 92.0% | Salesforce 10-K | documented annual rate |
| Apple | tech | 4.60 | 89.0% | Antenna churn data | documented annual rate |
| Spotify | gaming | 2.31 | 96.5% | Spotify earnings | documented annual rate |
| Netflix | gaming | 1.00 | 78.0% | Antenna churn data | documented annual rate |
| Zoom | saas | 0.90 | 92.0% | Zoom earnings | documented annual rate |
| Disney+ | gaming | 0.71 | 61.0% | Antenna churn data | documented annual rate |
Validation roadmap
Open challenges
- Single evaluator. All 184 platforms were scored by a single evaluator. This is the most critical methodological limitation. The reliability study is pre-declared, its protocol and cohort frozen by digest before execution, but recruitment is deferred — so this limitation stands until independent evaluators score that cohort.
- Two parameters have no recorded reference subject. Closeness and human fallback describe a state of the user rather than a property of the platform, and the rubric does not say which user. Coinbase’s closeness of 7 — “first interface opened each morning” — is reachable for an active trader and unreachable for the median registered account; because closeness multiplies capture directly, those two defensible readings put its B at 0.78 and 1.83 — values that fall in two different zones, Transition Zone and Event Horizon. No score is withdrawn and none is refuted: what is established is that these two parameters, as published, cannot be tested against evidence however good the evidence is. An attempt to evidence Coinbase’s closeness from audited SEC filings reached that conclusion on 8 September 2026, and the cloud-provider study had reached it independently on 22 August and recorded both parameters as not scorable. record
- Related rows are not independent measurements. Where one platform sits inside another’s corporate group, the two agree on 4.4 of the eleven parameters on average, against 2.7 for pairs merely in the same sector and 2.3 for pairs at random; in ten thousand random draws of twenty same-sector pairs, eleven reached that level. The effect is strongest in network effects (65% agreement against a 25% baseline) and portability, and it is weakest in closeness — refuting the hypothesis that prompted the test, which was pre-declared and hashed before any of it was computed. Two readings fit: related platforms genuinely resemble each other, or they were not scored independently. The record cannot choose, because the served dataset carries no recorded reasoning for 183 of 184 rows (platform-level rationales written for the 100 platforms of the Q1-2026 release were not carried into the database at the June 2026 migration; whether they are restored is a pending decision). One fact cuts against the second reading and is reported because it does: in thirteen cases a member scores above its parent on a capture parameter. No score is withdrawn; what follows is that ranking a platform against its own parent within one distribution has no basis in the record. record
- Sector heterogeneity. One scale is applied across every sector, and outside B = 1 no part of it is calibrated. B = 1 is definitional: the point at which capture equals escape. The four zone boundaries around it have no published derivation, and the zone names are interpretive labels rather than measured categories, so a comparison of rank or of relative position is better supported by this record than a reading of the absolute level. Sector-relative percentiles may be more useful than the global scale. Corrected 19 September 2026: this line read “The B-scale is calibrated globally”, in which the word calibrated asserted something this project does not hold and states the opposite of elsewhere.
- Time resolution. Quarterly cadence is coarse for fast-moving AI-platform dynamics. The quarterly record holds three observed vintages (Q1-2026 to Q3-2026); the Q4-2025 rows in the history are a modelled back-projection and are labelled as such.
- Causality. BHI is descriptive, not causal. Correlation does not establish causation.