What is a prediction market index?

A rules-based benchmark built from selected event contracts, calculated by an index provider rather than a venue.

Who calculates Adjacent's indices?

Adjacent is the calculating agent and publishes each index under its own methodology document.

How often are values updated?

Every 15 minutes on the public tier.

How do I read a level of 104.54?

Subtract 50 to get the implied probability, so 104.54 is a 54.5% implied chance.

Where is the methodology for a specific index?

Each ticker links to its PDF, and the same document is available as markdown by adding ?format=md.

Prediction market index methodology

Adjacent calculates prediction market indices with a published, rules-based methodology. Each index picks a universe of event contracts from Kalshi and Polymarket. It filters out stale or thin markets. It weights the rest by a stated rule and publishes a level every 15 minutes. Adjacent is the calculating agent, so every index has a formal methodology document, a version number and an effective date.

Universe

Each index names its venues, event family and eligibility rules in its methodology document.

Price to probability

A contract price in cents is read as an implied probability, and the methodology says which price is used.

Weighting

Constituents are included, held or excluded each compute cycle. A composite index holds child indices whose leaf weights the indexer resolves.

Scale

Political indices use a 50 to 150 scale where 100 is a 50/50 race. Senate (D) at 104.54 means a 54.5% implied chance of a Democratic Senate.

A total-return index starts at 100 and measures cumulative return. An index quoted in points, including the Misery Implied Index, uses the scale its methodology defines.

As of Nov 3 2026, Senate (D) is 106.16, House (D) is 108.15 and the Misery Implied Index (MSRY) is 8.13 percentage points.

Read the full method

Every other ticker is listed in the Governance catalog, as a PDF and as markdown (?format=md).

Frequently asked questions

What is a prediction market index? A rules-based benchmark built from selected event contracts, calculated by an index provider rather than a venue.
Who calculates Adjacent's indices? Adjacent is the calculating agent and publishes each index under its own methodology document.
How often are values updated? Every 15 minutes on the public tier.
How do I read a level of 104.54? Subtract 50 to get the implied probability, so 104.54 is a 54.5% implied chance.
Where is the methodology for a specific index? Each ticker links to its PDF, and the same document is available as markdown by adding ?format=md.

Definitions

Event contract: A contract whose value follows a defined event, such as an election. It settles on the outcome. It does not trade a continuous price forever.
Prediction market: A venue where event contracts trade, so their prices express a market-implied probability of the event happening.
Prediction market index: A rules-based benchmark built from selected event contracts. An index provider calculates it, not a venue.
Constituent: An event contract, or a child index, that an index holds. Each constituent carries a weight set by the index methodology.
Composite index: An index whose constituents are themselves indices. Leaf markets carry weights the calculating agent resolves.
Reference rate: A benchmark computed from prediction-market data and published as a percentage. It is for comparison across venues, not for trading.
Calculating agent: The party that computes and publishes an index according to its methodology. Adjacent is the calculating agent for the indices it publishes.
Settlement: How a venue resolves an event contract against its outcome. The venue records the resolution sources it names.

Sources

Page last reviewed: 2026-10-26.