Calculating Uncertainty
Uncertainty is the anticipated factor of uncertainty in a result, either due to random or systematic errors in measurement.
Uncertainty is a value, expressed as either a string or an absolute value that indicates the confidence in a numeric result that is derived from an analytical test.
Examples of a result and its uncertainty:
- String: 10.00 (<1)
- String: 10.00 (0.05%)
- Value: 10.00 (0.02)
- Value: 10.00 (0.15)
Uncertainty can be determined by various means, and is based upon the numeric value of the formatted final value.
If result for a sample scheme analyte is numeric, when a report is generated from a report request that has a Report Type of Certificate, then the report request sample scheme analyte's Uncertainty Value is calculated and rendered as a formatted string in the reporting objects.
Uncertainty Types and Values
Once the uncertainty value is calculated, then it is rounded and formatted for reporting. The rounding rules used to generate the rounded formatted report request sample scheme analyte's Uncertainty Value are the same as those used to generate the report request sample scheme analyte's Formatted Final Value. The type of uncertainty calculation is driven by the following scheme version analyte settings:
- Uncertainty Type
- Uncertainty Text
- Uncertainty Factor
- Uncertainty Range Table Code
- Uncertainty Script Code.
|
Uncertainty Type |
Formatted RRSSA Uncertainty Value |
|---|---|
|
None |
Report request sample scheme analyte's Uncertainty Value is set to N/A. |
|
Default Value |
Report request sample scheme analyte's Uncertainty Value is set to the string value of the following rounded value: |
|
Default Text |
Scheme Version Analyte Uncertainty Text |
|
Table |
Moving through the range table denoted by the scheme version analyte's Uncertainty Range Table Code, in the order of the range table item's Sequence Number, find the item where: The sample scheme analyte's Numeric Final Result >= the range table item's Lower Range Value and If no row is found then the sample scheme analyte's Uncertainty Value is left empty. If a row is found then: If the range table item's Return Text is not empty, then the sample scheme analyte's Uncertainty Value is set to the range table item's Return Text. If the range table item's Return Text is empty, then the sample scheme analyte's Uncertainty Value is set to the numeric value of the following value: Numeric value of the sample scheme analyte's Formatted Final Value x The uncertainty value is then rounded (using the same rounding method and configuration as the final formatted value), and is then available as the uncertainty (as a string value). |
|
Script |
The scheme version analyte's Uncertainty Text is set by the script denoted by the sample scheme analyte's Uncertainty Script Code. The script has access to: The scheme version analyte's Uncertainty Type, Uncertainty Text, Uncertainty Factor, Uncertainty Range Table Code The sample scheme analyte's Formatted Final Value The report request sample scheme analyte's Report Unit, Report Lower DL, Report Upper DL The scheme version analyte's Display Mask The sample, sample scheme, sample scheme analyte The job, client, project The scheme, scheme version, scheme version analyte The unit, unit conversion. |
Restrictions on Calculating Uncertainty
For sample scheme analytes associated with an org-scope scheme, where the ALLOW_REPORTING_UNCERTAINTY_OVERRIDE application preference is checked, the current lab-scope scheme version analyte properties are used to calculate the uncertainty for results. Where this preference is cleared, the org-scope properties are used to calculate the uncertainty for results.
See also: Set the ALLOW_REPORTING_UNCERTAINTY_OVERRIDE Preference.
Conditions for Using Org-scope or Enabled-scope Scheme Version or Scheme Version Analyte Attributes for Calculating Uncertainty
When a sample scheme analyte's uncertainty is calculated:
- If the sample is an org-scope template sample, then values of attributes in the org-scope scheme version and scheme version analyte are used for the calculation.
- If the sample is a lab-scope template, production, proposal, internal or laboratory batch sample, and the scheme is a lab-scope scheme, then values of attributes in the lab-scope scheme version and scheme version analyte are used for the calculation.
- If the sample is a lab-scope template, production, proposal, internal or laboratory batch sample, and the scheme is an org-scope scheme that is enabled for laboratory use, and the ALLOW_REPORTING_UNCERTAINTY_OVERRIDE application preference does not exist, or exists but is cleared, then values of attributes in the org-scope scheme version and scheme version analyte are used for the calculation.
- If the sample is a lab-scope template, production, proposal, internal or laboratory batch sample, and the scheme is an org-scope scheme that is enabled for laboratory use, and the ALLOW_REPORTING_UNCERTAINTY_OVERRIDE application preference exists and is checked, then the value of attributes in the lab-scope scheme version and scheme version analyte are used for the calculation.
Refer to the Effect of Scheme Scope upon Calculating Uncertainty in Workbook and Effect of Scheme Scope upon Calculating Uncertainty in Certificate Reports.
Persisting the Uncertainty
Although the report request sample scheme analyte's Uncertainty Value is calculated and rendered as a formatted string in the reportable result set so that it can be placed on a certificate report, it is only persisted to the report request sample scheme analyte's Uncertainty Value in the database, and to the sample scheme analyte's Uncertainty Value in the following circumstances.
| Report Request's Report Type | Report's Status Type | Persisted to Report Request Sample Scheme Analyte table? | Persisted to Sample Scheme Analyte table? |
|---|---|---|---|
|
Paperwork or Labels |
N/A (not calculated) |
No |
No |
|
Certificate |
Internal |
No |
No |
|
Certificate |
Preliminary or Final |
Yes |
No if the TRANSFER_RRSSA_REPORT_DATA_TO_SSA application preference is not defined, or is defined and cleared. Yes if the TRANSFER_RRSSA_REPORT_DATA_TO_SSA application preference is defined and checked. |
If a certificate report is generated with a Report Status Type of Final and the TRANSFER_RRSSA_REPORT_DATA_TO_SSA application preference is checked, when a result is rounded, then the sample scheme analyte's Formatted Final Value, Rep Lower Det Limit, Rep Upper Det Limit and Uncertainty Value are set to those on the report request sample scheme analyte.
If the TRANSFER_RRSSA_REPORT_DATA_TO_SSA application preference is cleared, inactive or not defined, then the sample scheme analyte's Formatted Final Value, Rep Lower Det Limit, Rep Upper Det Limit and Uncertainty Value are cleared, so as to ensure that no out-of-date values are persisted.
Refer to the Set the TRANSFER_RRSSA_REPORT_DATA_TO_SSA Preference.
The report request sample scheme analyte's and sample scheme analyte's Uncertainty Value can hold a string up to 40 characters.
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