LOEC Calculator
First actual independently significant tested concentration LOEC, retaining nonmonotone significance. This does not calculate pvalues, establish NOEC, true biological threshold or safe exposure.
Description
The lowest observed effect concentration is the first tested concentration with an independently established significant effect under the declared analysis.
The lowest observed effect concentration is the first tested concentration with an independently established significant effect under the declared analysis.1
It is a tested value rather than a true biological threshold.
When to use LOEC Calculator
Use this tool to calculate or review the supplied observations under the stated rules. Establish the chemical, exposure route, endpoint, measurement basis and independently applicable assay or assessment reference.
How to use LOEC Calculator and understand its results
- Establish the chemical, exposure route, endpoint, measurement basis and independently applicable assay or assessment reference.
- Enter actualTestedConcentrations, independentlyAssessedSignificantEffectFlags, using the field meanings and rules below, then run the tool.
- Read result.lowestObservedEffectConcentration, result.nonmonotoneSignificantEffectEvidence. Use the units and subtraction order below to interpret each value; retain negative differences where returned.
- Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| actualTestedConcentrations | Actual tested concentrations | list of number | Required |
| independentlyAssessedSignificantEffectFlags | Independently assessed significant effect flags | list of number | Required |
Supply at least two aligned nonnegative strictly increasing concentrations and binary independently assessed effect-significance flags. Return the concentration at the first one; an all-zero list fails. Set the nonmonotone flag if any later concentration has a zero flag. The tool neither tests significance nor requires a monotone flag sequence.
LOEC=concentration[firstIndex(flag=1)]; nonmonotone=any(flag_j=0 after first positive flag) Use the matching field units and the exact boundary, ordering and reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Qualified observed calculation or explicit reference | object |
| result.lowestObservedEffectConcentration | First tested concentration with an independently assessed significant-effect flag of one. | number |
| result.nonmonotoneSignificantEffectEvidence | True if a zero significance flag occurs after the first one. | boolean |
{
"input": {
"actualTestedConcentrations": [
1,
2,
3
],
"independentlyAssessedSignificantEffectFlags": [
0,
1,
0
]
},
"output": {
"result": {
"lowestObservedEffectConcentration": 2,
"nonmonotoneSignificantEffectEvidence": true
}
}
}Limitations and assumptions
Chemical identity, route, assay, exposure basis and reference applicability are caller-established. The output supplies no causal conclusion, universal toxicity threshold or authoritative regulatory determination.
Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Lists and matrices must be dense, without missing cells. Numeric lists allow at most 10000 entries, subject to the narrower lengths and code rules above. Extremely large composite outputs are rejected.
Alternative or Complementary methods
For a related step, use LOAEL to NOAEL Extrapolation Calculator: LOAEL-to-NOAEL extrapolation concerns an assessment adjustment between different observed-effect reference conventions. For a complementary comparison, use Acute to Chronic Extrapolation Calculator: Acute-to-chronic extrapolation concerns differences in exposure duration and response under a specified method.
References
-
LOEC Calculator — tool.io
Similar or alternative tools
- LOAEL to NOAEL Extrapolation Calculator
LOAEL-to-NOAEL extrapolation concerns an assessment adjustment between different observed-effect reference conventions.
- Acute to Chronic Extrapolation Calculator
Acute-to-chronic extrapolation concerns differences in exposure duration and response under a specified method.