NRFI and YRFI Probability Calculator

Use case and boundary

Estimate no-run and yes-run first-inning probabilities from expected scoring. Treat the entered event, selection, and period as part of the NRFI and YRFI Probability Calculator input set even though they are not numeric fields; keep the compared line fixed while making that check.

Starting pitcher, bullpen workload, park, weather, batting order, and handedness information must be current for the scheduled game. A final pre-comparison check for this page is that listed pitchers, official scoring, innings requirements, and postponement rules can determine whether the wager stands.

Formula and assumptions

The displayed rule is NRFI probability = e^(−combined first-inning expected runs).

For the NRFI and YRFI Probability Calculator, the Poisson zero-event probability converts expected scoring into the chance of recording no goals.

The NRFI and YRFI Probability Calculator reads Home first-inning expected runs on this basis: expected home runs in the first inning.

A correct formula still produces a poor comparison when fields use incompatible periods, prices, or scoring definitions; retain the original result for comparison.

Choosing values that belong together

Before calculating nRFI probability, check Away first-inning expected runs: expected away runs in the first inning; its timestamp should match the market comparison.

Use Home first-inning expected runs only on the basis printed beside the field; expected home runs in the first inning; a modeled value should be identified as such.

In the NRFI and YRFI Probability Calculator, Pitching and park adjustment adds another assumption: percentage adjustment to combined scoring expectation; keep its source with the result.

Rebuild nRFI probability after this condition: a pitcher or lineup change can make a saved projection obsolete before the market price visibly moves.

Compare this output with the First Five Innings Moneyline only when both calculations use the same event and timestamp.

Interpreting the headline and supporting values

For the NRFI and YRFI Probability Calculator, the displayed estimate is most useful as a comparison point when its source values and timestamp are retained; compare nRFI probability only with the same selection, period, and grading basis.

Change one uncertain field at a time so the reason for a moved result remains clear; do not use extra decimal places as a substitute for uncertainty.

The Baseball Moneyline Model may be the next useful step when the decision depends on it as well as nRFI probability.

NRFI probability in a worked case

For the NRFI and YRFI Probability Calculator, the values below differ from the form defaults; they make the method checkable and do not describe a recommended or typical wager.

Away first-inning expected runs is 0.538 runs; home first-inning expected runs is 0.473 runs; pitching and park adjustment is 0%.

Applying the NRFI and YRFI Probability rule: NRFI probability = e^(−combined first-inning expected runs).

Opposite outcome is 63.61%; adjusted expected events is 1.011.

For this nRFI probability example, a mismatch usually comes from units, rounding, a sign error, or a different option selection; check those items first.

When stolen base probability is part of the decision, use the Stolen Base Probability; its inputs answer a different question from nRFI probability.

Where this simplified method can fail

• Run scoring is modeled as Poisson and does not capture batting-order dependence.
• Confirm listed-pitcher conditions, innings covered, postponement rules, and whether extra innings are included.
• Settlement and data scope matter here because listed pitchers, official scoring, innings requirements, and postponement rules can determine whether the wager stands.

A bettor comparing this output with batter hits prop can open the Batter Hits Prop and keep the assumptions distinct.

Common questions about nRFI probability