Head-to-Head Weighting Calculator

Set the event before calculating

Begin with the question behind head-to-head adjusted probability—blend a baseline estimate with a selected weight for matchup history. Under the entered assumptions, another period or grading basis is a different question.

Both participants must use one rating scale and the same event conditions.

Market context

Fair price expresses model probability. It does not independently validate the rating.

For this market, fitness news or a surface change can make otherwise recent averages poor inputs.

For the saved case, surface, serve and return form, fitness, opponent, and likely match format should come from the same event.

The Tennis Game Handicap handles a different calculation and should open as a new case.

• At this stage, choose the least certain field and run one adverse case with other entries fixed.
• For this comparison, keep the new answer beside the baseline.
• As a practical check, a format, roster, participant, or settlement change calls for a new baseline.

Match every field to one event

• For the selected event, check the timestamp and unit for Baseline win probability because it supplies probability from the main model.
• Head-to-head wins belongs to the same period as the other entries. It is selected player wins in the matchup.
• Keep Head-to-head losses on the event basis defined here: selected player losses.
• Head-to-head weight is a separate input defined as share assigned to matchup history.

In this model, confirm that the baseline and adjustment did not both come from the same news.

The model provides a consistent answer for the selected assumptions.

Another participant definition or event length requires a new case.

For this comparison, a new market definition requires a new input set.

Meaning of the displayed number

Use the answer for the precise event scope entered here.

Do not extend it to another format without rebuilding inputs.

As a practical check, the answer is most useful as a baseline that can be updated.

For this market, follow the arithmetic once, then replace every figure with a sourced value.

For the Head-to-Head Weighting Calculator, use the worked case as a reproducibility check before entering live market assumptions. None of its values should be copied automatically.

Applying the Head-to-Head Weighting rule: weighted probability blends baseline model with head-to-head win rate.

Fair odds is -175. Head-to-head win rate is 66.67%. Baseline model is 62.72%.

For this head-to-head adjusted probability example, when the worked result differs, verify the field values one by one rather than changing several assumptions together.

Under the entered assumptions, a mismatch usually indicates a unit, percentage, odds-format, or rounding issue.

Practical limitations

• Small or outdated head-to-head samples should receive limited weight.
• At this stage, review retirement, walkover, best-of format, tiebreak, and completed-set rules before comparing a price.
• For the saved case, correlation, selection bias, and small samples can remain when every field has a source.

Documenting a market snapshot

Store head-to-head adjusted probability with event, selection, compared line, time, and source for Baseline win probability.

As a practical check, save enough context to reproduce head-to-head adjusted probability without form defaults.

For this comparison, do not overwrite the old case during a one-field test.

Questions raised by the calculation