When a statement of conformity to a specification is provided, NI utilizes decision rules and takes level of risk into account to determine conformance with the agreed specification for accredited and compliant calibrations.
By default, for test points the decision rule is the Binary Statement for Simple Acceptance Rule (see Figure 3). For test points with double-sided limits, a guard band is applied if the TUR is less than 4:1. For test points with a single-sided limit, a guard band is always applied. For test points where a guard band is applied (as noted in the status column on the calibration certificate), the decision rule is Non-Binary Statement with Guard Band2 (see Figure 4).
NI reports when guard banding is applied by displaying (1) in the status column of a calibration certificate for the applicable test point. NI reports conditional pass and conditional fail test points per the following:
- Measurement results determined to be conditional pass are denoted as Passedǂ in the status column of a calibration certificate.
- Measurement results determined to be conditional fail are denoted as Failedǂ in the status column of a calibration certificate.
Figure 3 Binary Statement for Simple Acceptance
Figure 4 Non-Binary Statement with Guard Band
Guard banding is only available with Accredited level calibration, and NI will automatically apply guard banding to the As Found calibration data for models that are enabled for guard banding. If conditional pass or fail results are found, customers should perform an impact assessment to determine if the conditional failed test data adversely impacts their products/processes.
1 Per ISO/IEC 17025:2017
2 As denoted in ILAC-G8:09/2019
3 Per ILAC-G8:09/2019 section 4.2.1