Methodology

How the edition was made: methods, the model card, the evidence cut and its age, the acceptance record and the glossary.

13 min read0 figures13 tables17 notesNR-XTECH-NEURO-GLOBAL-2026-BASELINE

Contents

A.1Methods

The global baseline uses published values and four simple derivations. Each is shown in full so that any reader can reproduce it.

Table A.1Methods
No.	Derivation	Calculation	Result
(1)	Ratio of median rate in² to rate in¹	78 ÷ 62	about 1.3 times
(2)	Gap between¹ and natural conversation as stated in¹	160 ÷ 62	about 2.6 times
(3)	Months from preprint to journal version of the accuracy study³	December 2023 to August 2024	8 months
(4)	Share of the 2025 round in the reported pre-money valuation²⁰	650 ÷ 9,000	about 7%

Table A.2Coupling strength scale (matrix and model card)
Strength	Definition
STRONG	a disruption in the source system has historically changed the target system’s service or output within one season, in more than one region
MODERATE	an effect is documented but buffered or slower
WEAK	an effect is plausible but not documented at global scale

Table A.3Status grammar
Label	Rule
Reported	value as issued by its source, with year
Inferred	reasoned from cited evidence; never a measurement
Estimated	Nexus analytical value with stated method
Scenario	conditional on stated assumptions
Expert input	structured editorial judgement awaiting evidence

A.2Model card, Neurotechnology System Model v0

Model ID: MDL-XT20-NEURO · v0.1
Purpose: represent neurotechnology as clinical hardware and a source of neural data coupled to health, materials, finance, workforce and privacy
Family: graph-based system of systems
Inputs: the cited sources of this edition; no proprietary data
Method: expert-specified coupling strengths (STRONG · MODERATE · WEAK) from assessments and analogue events
Validation: none yet, first validation against federation evidence in 2027
Uncertainty: qualitative; strengths are hypotheses, not measurements
Domain of validity: global scale; not for asset-, site- or country-level use
Reproducibility: strength table and sources published in this edition

20couplings

typed in v0

0strong

documented within one season

0moderate

documented, buffered

20weak

plausible, undocumented

A.3The baseline evidence cut

Every Nexus edition is published from a frozen evidence cut. The global baseline cut is documentary: it pins the exact edition of every source cited. Federation cuts begin with the first national Foundry cuts in 2027.

Cut ID: DC-XTECH-NEURO-GLOBAL-2026-B0
Type: baseline documentary cut
Resolution policy: pinned · as of 30 September 2026
Sources pinned: 44 cited sources, each at the edition and access date in the references
Model runs: none at baseline, analytical values are stated with their method
Digest: computed at freeze and recorded in the publication record
Supersedes: nothing, first cut of the series
Superseded by: the 2027 neurotechnology annual cut

Lineage

01
source edition
02
pinned citation
03
finding
04
page
05
publication record

Table A.4From the baseline cut to the federation cut
Element	Baseline 2026	2027 global annual
Sources	cited global publications, pinned by edition	national, regional and sector cuts through one graph
Analysis	stated methods and editorial estimates	typed analysis specifications
Models	Neurotechnology System Model v0 specification	model runs with receipts
Findings	twelve baseline findings	findings re-bound to federation evidence
Review	five passes scheduled	five passes on the exact digest

A.4Evidence age and coverage

A 2026 global edition rests on evidence observed in many different years. This page shows each time base, so that no single year label hides older evidence.

Table A.5Evidence age and coverage
Indicator	Observed	Released	Cadence	Next release
Speech decoding papers	2023	Aug 2023	one-off	follow-up papers
Speech accuracy over time	2023 preprint · 2024 journal	Dec 2023 · Aug 2024	one-off	more participants
Brain-spine interface	2023	May 2023	one-off	longer follow-up
Endovascular study	2025	Sep 2025	one-off	peer-reviewed version
PRIME registry entry	2026	Jan 2026	continuous	next update
US neural data bill	2025	Sep 2025	per session	committee action
UNESCO Recommendation	2025	Nov 2025	one-off	national uptake
Chinese implementation opinion	2025	Jul 2025	periodic	2027 milestones

Table A.6Coverage by system at baseline
System	Coverage	Thinnest dimension
Hardware	PARTIAL	failure rates on a common basis
Clinic	PARTIAL	outcomes beyond one year
Neural data	PARTIAL	consumer practices
Governance	PARTIAL	text of national laws
Investment	THIN	market size and public funding
Energy and heat	THIN	power and heat budgets
Skills	THIN	workforce numbers
Materials	THIN	dependence by platform

Table A.7Designed empty states: what is not bound, what would fill it and why
Field	Source that would fill it	Blocker
Power and heat budgets of implanted interfaces	device makers, regulators, peer-reviewed engineering papers	no figure retrieved; the search for heating and power limits returned no quantitative source
Market size on a common definition	industry statistics and audited company reports²⁹	trade sources give widely different figures by definition; none was opened
Clinical workforce for implantation, programming and follow-up	national statistics, professional bodies	not retrieved; capability rung stays LISTED
Long-term failure and explant rates across platforms	trial reports, registries, manufacturers	only one-year results read⁷⁸; no common reporting
Number of participants implanted per company	company reports and registry updates¹³²⁰²⁶	company statement of 5 in June 2025; a January 2026 report of 21 is secondhand and unverified
Peer-reviewed results for company-announced devices	journals for each company claim¹⁵²⁷	company releases only; no paper located
Consumer neural data practices by company	regulators, advocacy and academic audits³³	report not opened; no figure used
Text of California, Montana and Connecticut neural data laws	state legislature sites²⁵⁴¹	California page returned an access error; the others not retrieved
Public funding totals for neurotechnology programmes	ministries, research councils	the national research programme budget page returned an access error
Electrode materials and fabrication dependence by platform	industry and trade statistics	only a 2018 materials roadmap abstract read²³
Status of the MIND Act after referral to committee	congressional record	status read from bill text and a release only
Reimbursement and access to implants by country	health ministries, insurers	not reviewed
Wearable and non-invasive interface deployment data	companies, regulators	one paper named from memory³²; no figure used
Capability rungs beyond guidance and planning	agencies, hospitals, laboratories	not reviewed

A.5Evidence cards, two anchor sources

Published in Nature 620 (2023) by a Stanford-led group. One-off study. Role: binds INF-001 and the speech tiles. Coverage: one participant with ALS and four intracortical arrays.

EVD-XT20-001

A high-performance speech neuroprosthesis¹

Introduced in the US Senate in 2025 as S. 2925. One-off text. Role: binds GOV-009. Coverage: US federal study of neural data; status was committee referral.

EVD-XT20-002

MIND Act of 2025 bill text¹¹

Table A.8Quality dimensions at baseline
Dimension	EVD-XT20-001	EVD-XT20-002
Completeness	one participant; 50-word and 125,000-word vocabularies	full bill text; later status not read
Timeliness	published online 23 August 2023	introduced 2025
Revision	single paper version	amendments possible in committee
Method transparency	methods and data in the paper	text public
External validation	peer review	legislative process

Evidence cards to follow in 2027

Willett et al.¹: replication in more participants
Chetty et al.⁸: peer-reviewed version
MIND Act¹¹: committee action
Registry entry¹³: updated enrolment

A.6Publication acceptance record

Editorial self-check at evidence close. Every applicable item carries a disposition; the remaining items are review, approval and deposit.

Table A.9Publication acceptance record
Group	Area	Items	Pass	N/A	Pending
D1	Identity and scope	8	8	0	0
D2	Source and data	12	9	1	2
D3	Analysis and models	12	3	8	1
D4	Findings and claims	9	8	0	1
D5	Figures, tables, maps	10	6	2	2
D6	Editorial and citations	10	8	0	2
D7	Review and approval	13	0	0	13
D8	Artefact and design	12	7	0	5
D9	Registry and release	9	0	0	9

Publication gate

Conditions met: 14 of 23 at evidence close
Blocking problems: none recorded
Open conditions: reviews, approval of the exact digest, deposit, registry pointer

Not applicable at baseline

Model runs: first runs in Q1 2027
Maps: plates in Q2 2027
Waivers: none

A.7Status words

Table A.10The status every value carries
Status	What it means
Observed	Measured directly and published by the source.
Reported	Published statistics of an official or institutional source.
Declared	Stated by the body concerned; not independently measured.
Estimated	A Nexus estimate from cited evidence, with its method in Annex A.
Modelled	Produced by a stated model from cited inputs.
Inferred	Reasoned from cited evidence; not measured.
Forecast	A projection by the cited source.
Simulated	A simulation result under stated assumptions.
Scenario	A conditional statement under stated assumptions; never a prediction.
Expert input	Expert judgement, recorded with its basis.
Candidate	Proposed for a later edition; not yet evidence.
Evidence-quality levels (EQL 1 to 5) grade the source behind a value; they are not a score of the subject.

A.8How the edition is made, released and corrected

Every edition is built from a sealed evidence cut, reviewed under three keys, signed and deposited before any site shows it as published; corrections go to Nexus Standards as change proposals and feed the next cut.

Step	What happens	Source
01 Evidence arrives from the pillars	Foundry seals observations and indicator series, Universe hands over after-action and scenario findings, and contributions are screened at every gateway, including this site’s.
02 The cut is sealed	On the cut date the evidence is pinned under one identifier, so anyone can rebuild the edition from exactly what it was built on.
03 The edition is assembled	The edition is drafted from its template and content pack. Agents may draft; they never publish and never decide.
04 The keys turn	At the publisher of record the truth key comes first: every value is checked against its source or stated method before the meaning and capital keys turn. No edition moves on until every key has been turned by a named steward.
05 The gate opens	A named approver releases one exact digest of the edition; any change after this point is a new version, never a silent edit.
06 Signed and deposited	The PDF, the web edition and the data bundle are signed together with a manifest and an RO-Crate description, and deposited on Zenodo with a concept and a version DOI.
07 Published on its desk’s site	Only then does the edition show as published on its desk’s Reports site, and the Collection lists it as a part.
08 Corrections go to Standards	Method and correction findings go to Nexus Standards as change proposals; citations, corrections and new contributions feed the next evidence cut.

A teaching model of the process, not a forecast and not a record of any run; dates and counts on this page come from the programme record. Sources: Reports governance at GCRI Canada (2026); Zenodo, repository of record for Reports deposits (2026).

Lifecycle, one state at a time: Draft, Computed, Evidence bound, Reviewed, Approved for release, Published, Corrected, Superseded. This edition is a draft.

A.9Glossary and abbreviations

Table A.11Series terms
Term	Meaning
Baseline Edition	the inaugural annual edition that fixes the reference state for the series
WEFH+B	water, energy, food, health and biodiversity, the national nexus core
Coupling	a typed dependency through which one system transmits to another
Protection gap	the share of losses not covered by insurance
Capability ladder	LISTED → EXISTS → ADEQUATE → TESTED → DEMONSTRATED
EQL	evidence-quality level, 1–5
Evidence cut	a frozen resolution of exact sources and versions
NNC · NLC · NWG	National Nexus Consortium · National Leadership Council · National Working Groups

Table A.12Abbreviations used in this edition
Abbreviation	Expansion
ALS	amyotrophic lateral sclerosis
BCI	brain-computer interface
DBS	deep brain stimulation
EFS	early feasibility study
FDA	US Food and Drug Administration
FTC	US Federal Trade Commission
IDE	investigational device exemption
MIND	Management of Individuals Neural Data
MIIT	Ministry of Industry and Information Technology of China
PRIME	Precise Robotically Implanted Brain-Computer Interface study
UNESCO	United Nations Educational, Scientific and Cultural Organization
WER	word error rate

A.10Technical annex

Table A.13Technical annex
Item	Annex	Contents	Status
A.1	Indicator definitions	the global indicator set, with units and sources	IN THIS EDITION
A.2	Coupling strengths	the twenty-cell matrix and its rationale	IN THIS EDITION
A.3	Scenario specification	SCN-XT20-NDT-01 assumptions and signposts	IN THIS EDITION
A.4	Capability placements	rung evidence for fifteen functions	IN THIS EDITION
A.5	Model diagnostics	first runs and validation	2027
A.6	Sensitivity analyses	influence of coupling strengths	2027
A.7	Cluster notes	cards for the major clinical interface clusters	2027
A.8	Review statements	pass-by-pass review record	AT RELEASE

A.1 · indicator definition: word error rate

Construct: share of decoded words that differ from the words the participant intended to say
Unit: percent
Method: attempted speech decoded by a trained model from implanted electrode signals, scored against the intended sentences
Source: Nature 620 (2023)¹²
Uncertainty: as reported by the authors; not restated here
Known limits: one participant per study; sentences and vocabulary set by the researchers

Notes

Numbers are the edition’s reference numbers, so a note reads the same in every chapter. The full list, with every source and its licence, is in Annex C. Annex C, references

2Metzger, S.L. et al., A high-performance neuroprosthesis for speech decoding and avatar control, Nature 620(7976), 1037 to 1046, published online 23 August 2023 (reference record read: median 78 words per minute; median word error rate 25%). Springer Nature, London. Observation year 2023. Accessed 2026-11-03.back
1Willett, F.R. et al., A high-performance speech neuroprosthesis, Nature 620(7976), 1031 to 1036, published online 23 August 2023 (reference record read: 62 words per minute; 23.8% word error rate on 125,000 words; 9.1% on 50 words). Springer Nature, London. Observation year 2023. Accessed 2026-11-03.back
3Card, N.S. et al., An accurate and rapidly calibrating speech neuroprosthesis, medRxiv preprint, 26 December 2023 (preprint record read: 99.6% on 50 words on day 1; 90.2% on 125,000 words on day 2; 97.5% beyond eight months; 256 electrodes; the record notes the New England Journal of Medicine version 391(7), 609 to 618, August 2024). Cold Spring Harbor Laboratory, New York. Observation year 2023. Accessed 2026-11-03.back
20Zeff, M., Elon Musk Neuralink closes a USD 650 million Series E (trade report, 2 June 2025; page read; vendor statement as reported: five people implanted; valuation of about USD 9 billion pre-money from an earlier press report). TechCrunch, San Francisco. Observation year 2025. Accessed 2026-11-03.back
29UNVERIFIED, not opened: market-research reports on the neurotechnology and brain-computer interface markets for 2025 (several firms; figures differ by a large factor depending on definition), taken from search-result summaries; weak evidence and no figure used. Observation year 2025. Accessed 2026-11-03.back
7Lorach, H. et al., Walking naturally after spinal cord injury using a brain-spine interface, Nature 618(7963), 126 to 133, published online 24 May 2023 (reference record read: fully implanted; stable for over one year; one man with chronic tetraplegia). Springer Nature, London. Observation year 2023. Accessed 2026-11-03.back
8Chetty, N. et al., Signal properties and stability of a chronically implanted endovascular brain computer interface, medRxiv preprint, 25 September 2025 (preprint record read: five participants; 16-channel array; one year; not peer reviewed). Cold Spring Harbor Laboratory, New York. Observation year 2025. Accessed 2026-11-03.back
13ClinicalTrials.gov (ed.), PRIME: An Early Feasibility Study of a Precise Robotically Implanted Brain-Computer Interface for the Control of External Devices, NCT06429735 (record read: recruiting; start 9 January 2024; estimated enrolment 15; updated January 2026; sponsor-supplied entry). National Library of Medicine, Bethesda. Observation year 2026. Accessed 2026-11-03.back
26UNVERIFIED, not opened: report of January 2026 that Neuralink was enrolling 21 participants worldwide, taken from a search-result summary of a secondhand news item citing people familiar with the matter; weak evidence. Observation year 2026. Accessed 2026-11-03.back
15Precision Neuroscience (ed.), company release on FDA 510(k) clearance of the Layer 7 Cortical Interface, 17 April 2025 (release read; vendor announcement, weak evidence: up to 30 days of implantation; 37 patients tested). Precision Neuroscience, New York. Observation year 2025. Accessed 2026-11-03.back
27UNVERIFIED, not opened: Paradromics (ed.), company statements on an FDA investigational device exemption for the Connect-One early feasibility study (November 2025, two initial participants) and a first implant at a university hospital, taken from search-result summaries of vendor announcements; weak evidence. Paradromics, Austin. Observation year 2025. Accessed 2026-11-03.back
33UNVERIFIED, not opened: Neurorights Foundation (ed.), report on privacy practices of consumer neurotechnology companies, 2024, cited from memory without figures; the foundation page returned not found. Neurorights Foundation, New York. Observation year 2024. Accessed 2026-11-03.back
25UNVERIFIED, not opened: California Senate Bill 1223 (Becker), consumer privacy: sensitive personal information: neural data, signed 27 September 2024, in force 1 January 2025, taken from search-result summaries; the legislature page returned an access error. California Legislature, Sacramento. Observation year 2024. Accessed 2026-11-03.back
41UNVERIFIED, not opened: Montana and Connecticut state laws on neural data, named in the Senate release [12] and in search-result summaries; texts not opened. State legislatures, Helena and Hartford. Observation year 2025. Accessed 2026-11-03.back
23Wellman, S.M. et al., A materials roadmap to functional neural interface design, Advanced Functional Materials 28(12), 2018 (reference record read; no figures in the abstract). Wiley, Weinheim. Observation year 2018. Accessed 2026-11-03.back
32UNVERIFIED, not opened: Meta Reality Labs research team, paper on a wrist-worn electromyography interface for generic human-computer interaction, Nature 2025, cited from memory; the Nature page redirected to an access check. Springer Nature, London. Observation year 2025. Accessed 2026-11-03.back
11United States Senate (ed.), Management of Individuals Neural Data Act of 2025 (MIND Act), S. 2925, 119th Congress, introduced text (text read: FTC study and report within one year of enactment; USD 10 million authorised; referred to committee). US Government Publishing Office, Washington. Observation year 2025. Accessed 2026-11-03.back

Cite this annex

Valadbaygi, S. (Ed.). (2026). Annex A: Methodology. In Exponential Technology Report 2026: Neurotechnology and Human–Machine Interfaces (Baseline Edition 2026, Report No. NR-XTECH-NEURO-GLOBAL-2026-BASELINE) [Draft under review]. The Global Centre for Risk and Innovation (GCRI).

Every citation form of the whole report, BibTeX and RIS included, is on the edition home. Cite this report

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