Description
Return false-match rate under an excluded-count denominator policy.
Biometric scores depend on matcher version, score direction, acquisition handling and an explicit operating threshold. Score transformations and observed error fractions are different from identity verification; equality, quantization and excluded attempts can change the local reported result.
Return false-match rate under an excluded-count denominator policy.
When to use this tool
Use Biometric False Match Count Denominator when checking the stated biometric score, threshold, reporting precision or error-denominator convention.
How to use the tool and how it works
- Enter falseMatches, nonmatchComparisons, excluded, includeExcluded. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read denominator, falseMatchRate. Use the output convention below.
Return false-match rate under an excluded-count denominator policy. Require positive whole nonmatchComparisons, falseMatches within it and excluded >= 0; denominator adds excluded only when includeExcluded, numerator remains falseMatches.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| falseMatches | False Matches | Required. Safe integer; minimum 0. |
| nonmatchComparisons | Nonmatch Comparisons | Required. Safe integer; minimum 1. |
| excluded | Excluded | Required. Safe integer; minimum 0. |
| includeExcluded | When true, excluded count is added to denominator only. | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| denominator | Denominator | Required. Safe integer. |
| falseMatchRate | False Match Rate | Required. Finite number. |
{
"input": {
"falseMatches": 2,
"nonmatchComparisons": 1000,
"excluded": 100,
"includeExcluded": false
},
"output": {
"denominator": 1000,
"falseMatchRate": 0.002
}
}Limitations and assumptions
- Excluded cases are not classified as matches; the policy changes reporting without proving operational error rates or fairness.
- 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
Evaluate a validated matcher on relevant complete data with explicit acquisition/exclusion and threshold policies; assess uncertainty, privacy and fairness independently.
References
Similar or alternative tools
- Biometric False Nonmatch Count Denominator
Return a false-nonmatch reporting rate under acquisition-failure inclusion.
- Biometric Failure Acquisition Share
Return acquisition-failure rate and usable-acquisition count.