Description
If belowDetection is true, use detectionLimit times the fraction; otherwise retain reportedValue.
Geochemical normalization compares a measurement with a supplied reference or reporting basis. Ratios remove compatible units, while rescaled concentrations retain a unit; a chosen reference is an assumption rather than an independently verified material standard.
If belowDetection is true, use detectionLimit times the fraction; otherwise retain reportedValue.
When to use this tool
Use Geochemical Detection Limit Substitution Flag when you need one reference-normalization or reporting-convention calculation.
How to use the tool and how it works
- Enter reportedValue, detectionLimit, belowDetection, substitutionFraction. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read analysisValue, substituted, exceedsReportedLimit. Inspect substituted, exceedsReportedLimit before interpreting the associated values.
Require nonnegative detectionLimit and substitutionFraction in [0, 1]. If belowDetection is true, use detectionLimit times the fraction; otherwise retain reportedValue. Also flag a below-detection label paired with a reported value above its limit.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| reportedValue | Reported Value | Required. Finite number. |
| detectionLimit | Detection Limit | Required. Finite number; minimum 0. |
| belowDetection | Below Detection | Required. Boolean. |
| substitutionFraction | Substitution Fraction | Required. Finite number; minimum 0; maximum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| analysisValue | Analysis Value | Required. Finite number. |
| substituted | Substituted | Required. Boolean. |
| exceedsReportedLimit | Exceeds Reported Limit | Required. Boolean. |
{
"input": {
"reportedValue": 0.2,
"detectionLimit": 1,
"belowDetection": true,
"substitutionFraction": 0.5
},
"output": {
"analysisValue": 0.5,
"substituted": true,
"exceedsReportedLimit": false
}
}Limitations and assumptions
- Below-detection status is caller supplied, not inferred. A substituted number is an analysis convention rather than a measured concentration; no universal substitution policy or censored-data statistical method is endorsed.
- 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
Use the complete analytical method and appropriate reference materials for interpretation. Align concentration units, dry/wet basis, detection-limit handling, and reference provenance before comparing samples.
References
Similar or alternative tools
- Trace Element Reference Gap
Return measured minus reference, that difference divided by reference, and that difference divided by the quantum.
- Sample Dry Mass Support Share
Sum mass times (1-moisture), separately for supported rows, then return their ratio or zero with defined false when total dry mass is zero.