Methodology changelog

v0.7 — 2026-07-01 (current)

Period comparison switched from WoW to MoM

• MoM replaces WoW. The period delta published alongside each index level is now month-over-month (28-day lookback) rather than week-over-week (7-day). The comparison window is the current rolling 7-day median vs. the same 7-day window 28 days prior. Field name in indices.json changed from wow_pct → mom_pct. Rationale: secondary GPU markets can go 8+ days without a credible completed transaction; a 7-day comparison amplified collection-density noise rather than genuine price signal. The 28-day window stabilizes medians across collection gaps and matches the natural frequency of physical infrastructure pricing, analogous to ISM/Markit PMI methodology. First MoM delta published with Issue 2 (2026-07-13).

v0.6 — 2026-06-03/04

PRA hardening + multi-vendor sourcing

• SWCI frontier component multi-sourced. The 35%-weight Frontier GPU OEM component was discovered to be 100% single-vendor (Supermicro via Thinkmate). Dell publishes no public frontier-node price (quote-only); CDW doesn't list frontier nodes. Two independent integrator sources added (Exxact, Bizon — B200/H200/MI300X configurator list prices). frontier_n_sources 1 → 3.
• Single-source guard. New single_source_warning flag: fires when a component at ≥15% weight rests on fewer than 2 independent price vendors. Was true at introduction; cleared by the multi-sourcing. Permanent — if a vendor feed dies, the index re-flags itself.
• Per-accelerator normalization. Frontier node prices now also published per accelerator (frontier_per_accelerator_value), commensurable with the per-card legacy GPU component. Rack-scale SKUs (GB200 NVL72) excluded.
• Price-primitive disclosure (SWCI + SWII). Every component tagged with the kind of price it carries (ebay_transacted / oem_list / channel_list / cloud_quoted / stress_proxy). A list price is not a transacted price; the data now says which is which.
• Condition-consistency (SWCI legacy GPU). The secondary GPU basket now assesses a consistent used-working spec, excluding premium (New/Refurb/Open Box) and parts/broken tiers. Measured effect −2% to +10% per SKU, direction varying — the prior mix was composition noise. Disclosed as gpu_condition_basis.
• Source-tier relabel. frontier_gpu and nvswitch_oem relabeled tier_1_oem_direct → tier_2_integrator_channel_survey — OEM-direct frontier pricing is quote-only; what we survey is the integrator channel, and the label now says so.
• SWII vendor-concentration guard + interconnect survey. New vendor_concentration_warning (fires at ≥40% single-vendor weight); correctly flagged FS.com at 60% at introduction. Three independent vendors added — ColfaxDirect (NVIDIA/Mellanox InfiniBand NDR/HDR/XDR at real part numbers), QSFPTEK, 10Gtek. Survey status is per-component and data-driven (≥2 vendors AND no vendor >75% of priced comps). All three former FS-only components now qualify; FS.com single-vendor exposure 60% → 0%. Per-component vendor shares published.
• Open data. Per-index history CSVs (provenance-labeled rows), machine-readable methodology.json, frozen monthly archives, /cite formats, and stable issue permalinks (/v/I/{issue}).

v0.5 — 2026-06-02

Comp integrity + multi-year history

• GPU comp composition cleanup. Secondary-market GPU ingest now excludes multi-unit lots, parts/non-working listings, and datacenter cards priced below a physical-implausibility floor. A100 80GB PCIe intra-window dispersion fell 8.55x → 4.29x — the median now tracks single working cards, not listing mix.
• Multi-year sold-comp backfill. First-party transaction records extend GPU comp history to mid-2023 for key SKUs (A100 80GB PCIe: 5 months/19 comps → 25 months/74 comps). Backfilled rows are provenance-tagged and pass the same cleanup.
• Cluster Valuator dataset. Per-SKU secondary medians + empirically measured vintage decay curves (A100 80GB PCIe ≈ −54%/yr, V100 32GB PCIe ≈ −36%/yr, H100 ≈ flat), cited condition/liquidation anchors, confidence bands, coverage-tier flags. Condition factors are cited anchors — eBay condition tags proved too noisy to derive them, and the methodology says so.
• Depreciation cross-validation dataset. Disclosed accounting useful lives from 13 SEC filers vs SpotWire-measured secondary decay, with useful-life-change events and filing URLs as receipts.

v0.4 — 2026-05-29

• Component weights for SWPI and SWFI revised to research-derived values with sensitivity analysis (RT-7)
• Per-component n_comps (volume) now exposed in indices.json and on the public site (RT-11)
• EDGAR text-mining lead-time regex widened — SWPI flips to LIVE (FU-1)
• SEC EDGAR access refactored to use marketkit shared library

v0.3 — 2026-05-29

• SWFI composite goes LIVE — first composite to drop the Indicative badge (P3-T8)
• SWPI upgraded from spot-power-only to full diffusion (4/5 components active, P3-T5)
• BLS PPI scraper covering 9 series across SWPI and SWFI cohorts (P3-T4, P3-T6)
• EDGAR mining for SWFI cohort: Vertiv, Trane, JCI, Rockwell, Honeywell, Dover, Emerson (P3-T7)

v0.2 — 2026-05-28

• SWCI compositor lands — first composite computed from real SpotWire data-engine comps
• Historical YoY backfill for SWCI basket: 71 source-attributed monthly points across 17 SKUs (P1-T7)
• EDGAR mining for SWPI cohort: Quanta, MasTec, GE Vernova, Eaton, Hubbell (P3-T3)
• EIA-860M, LBNL Queued Up, FS.com, gridstatus — five new data sources powering SWPI (P3-T1, P3-T2, P2-T1, P2-T4)
• SSD pipeline unstranded; DDR5/DDR4 RAM scraper added to SWCI basket (P1-T1+T2)

v0.1 — 2026-05-27

• Initial four flagship composite indices defined: SWCI, SWII, SWPI, SWFI
• All four start as v1 hand-curated mock values, labeled Indicative