ISO 11843-2:2000

Overview

ISO 11843-2:2000 - Capability of detection, Part 2: Methodology in the linear calibration case defines statistical methods to design experiments and estimate detection characteristics for measurement systems whose calibration function is linear. It describes how to compute the critical value of the response, the critical value of the net state variable, and the minimum detectable value (MDV) for measurement series when the residual standard deviation is either constant or linearly dependent on the net state variable. The standard is intended for continuous quantities and measurement procedures that use calibration relationships.

Key topics and requirements

• Scope & assumptions
  • Applicable when the expected response vs. state variable relationship is linear.
  • Measurement errors are assumed independent and normally distributed (residual standard deviation either constant or linear in the net state).
• Experimental design
  • Use multiple reference states including the basic state (zero net state) and at least one near the expected MDV.
  • Recommended number of reference states: I ≥ 3 (I = 5 recommended).
  • Replications: identical numbers of preparations (J) and repeated measurements (L) for each reference state; J ≥ 2, L ≥ 2 recommended.
  • Practical advice: split calibration measurements before/after unknown sample analysis to detect time-dependent bias.
• Estimation & computation
  • Procedures to estimate calibration parameters (slope/intercept) and residual standard deviation.
  • Formulae (given in the standard) to compute critical response value (y_c), critical net state (x_c), and minimum detectable value (x_d) for a measurement series.
• Reporting and use
  • Guidance on reporting critical values and MDV for a measurement series, a laboratory, or a measurement method.
• Supporting material
  • Annex A: symbols and abbreviations (normative).
  • Annex B: derivation of formulae (informative).
  • Annex C: worked examples (informative).

Applications and users

ISO 11843-2:2000 is valuable for organizations that must quantify detection capability and set decision thresholds:

• Analytical chemistry and trace analysis laboratories determining detection limits.
• Environmental testing, food safety, pharmaceutical quality control for presence/absence decisions.
• Metrology institutes and testing laboratories validating measurement methods and instruments.
• Instrument manufacturers and statisticians implementing calibration-based detection performance assessment.

Practical uses include selecting appropriate measurement methods, validating laboratory performance, establishing decision criteria for presence/absence, and supporting conformity assessments where detection capability must be quantified.

Related standards

• ISO 11843-1:1997 - Terms and definitions (Capability of detection).
• ISO 11095:1996 - Linear calibration using reference materials (basis for calibration assumptions).
• ISO 3534 series and ISO Guide 30 - statistical and reference material terminology.

Keywords: ISO 11843-2:2000, capability of detection, linear calibration, minimum detectable value, critical value, residual standard deviation, calibration function, detection limit, experimental design, analytical chemistry.