Benchmark Governance

A benchmark is only as useful as the discipline behind its publication. Before an institution cites an index in a risk report, references it in research, or licenses it as an underlying, the questions it asks are not about the formula – the formula is published – but about administration: Who can change the methodology, and how? Are published values ever rewritten? What happens when the data is bad? Will the history still mean the same thing in five years? This page answers those questions in one place.

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Methodology Versioning

Every published computation records the methodology version it was produced under (currently midprice-v1).

• Revisions are dated and prospective-only. A methodology change applies to future computations, never retroactively to published history. The same rule governs selection and weighting thresholds: revisions apply to future selections, never to existing compositions.
• Changes are announced and documented. Any methodology change is disclosed in advance, and the version history is published in NAV Methodology.
• Judgment is exercised once, in public. Where human judgment enters index construction – theme definition and the documented judgment screens – it is applied at composition time under published criteria. There is no ongoing discretionary adjustment of a live series.

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Corrections Policy

As-published values are preserved as published. If an error in a published level is identified, the correction is issued as a new, labeled computation – the original value is not silently overwritten. This mirrors the discipline of the underlying fund accounting, where existing ledger entries are never edited or deleted; adjustments are made through new, compensating entries. The practical consequence for data users: the series you observe at any point in time is the series everyone observed. A backtest run against Belief Index history is a backtest against what was actually published – no silent revisions, no hindsight.

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Publication Integrity

The pipeline is designed to disclose data-quality problems rather than publish through them:

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The Point-in-Time Archive

Prediction market order books are ephemeral: quotes are not archived the way equity prices are, and resolved contracts disappear from venue interfaces. A themed probability series reconstructed after the fact is contaminated by hindsight – which markets to include, how to splice across resolutions, which prices to trust are all choices made knowing the outcome. Belief Index levels are computed and recorded as of each valuation window, live, under the versioning and corrections discipline above. The result is a point-in-time record of how markets actually priced each theme – with no lookahead, no survivorship filtering, and no retroactive splicing. Each series’ full computation history is preserved, including staleness flags and methodology versions, so a future reader can know not just the level but the data quality behind it. This archive is treated as the crown jewel of the operation. It compounds with every published window, and no part of it can be rebuilt later.

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Data Sources

Levels are currently computed from order book data supplied by a single prediction market venue. This is disclosed plainly rather than obscured: see Single Data Source for what it means for data users. The methodology itself is venue-agnostic – selection screens, weighting, and valuation are specified in terms of observable order book quantities, not venue-specific features. Incorporating additional venues as they meet the eligibility screens is the natural evolution of the methodology, and any such change would follow the versioning discipline above.

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Reference Framework

The administration practices on this page – published methodology, versioned and prospective-only changes, a corrections policy, data-quality disclosure, and documented use of judgment – are informed by the IOSCO Principles for Financial Benchmarks, the international reference framework for benchmark administration. Belief Systems does not claim formal compliance with, or external assurance against, those principles; they serve as the design benchmark the administration practices are built toward as the index family matures.

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Further Reading