Relative Skill Zero Baseline Policy Tool

Description

For nonnegative loss and positive baseline return 1 - loss / baseline.

A skill comparison expresses performance relative to a reference loss or scale. Zero baselines and orientation choices can make a nominal score undefined or reverse its interpretation.

For nonnegative loss and positive baseline return 1 - loss / baseline.

When to use this tool

Use Relative Skill Zero Baseline Policy when you need an explicit baseline-relative error or equality term.

How to use the tool and how it works

Enter loss, baseline, zeroValue. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read defined, score. Inspect defined before interpreting the associated values.

For nonnegative loss and positive baseline return 1 - loss / baseline. At baseline zero use the caller's zeroValue and set defined false.^[1]

Input field	Meaning and units	Accepted input
loss	Loss	Required. Finite number.
baseline	Baseline	Required. Finite number.
zeroValue	Zero Value	Required. Finite number.

Output field	Interpretation	Returned shape
defined	Whether the accompanying numeric result has an available denominator or required inputs.	Required. Boolean.
score	Score under the explicit mathematical and availability conventions above.	Required. Finite number.

json

{
  "input": {
    "loss": 0,
    "baseline": 0,
    "zeroValue": 0
  },
  "output": {
    "defined": false,
    "score": 0
  }
}

Limitations and assumptions

zeroValue is a policy placeholder; it does not resolve the mathematical undefined case or establish baseline suitability.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Check baseline suitability and aggregate losses on comparable observations before interpreting relative performance.

References

Calculation and input contract: metrics/relative-skill-zero-baseline-policy — tool.io

Similar or alternative tools

Skill Score Sign Reference Choice
Return modelLoss / referenceLoss - 1 when higherIsBetter, otherwise 1 - modelLoss / referenceLoss.
Forecast Skill Baseline Equality Point
Subtract baselineLoss from modelLoss for residual.