ISO 17994:2014 specifies an evaluation procedure for comparing two methods with established performance characteristics according to ISO/TR 13843 and intended for the quantification of the same target group or species of microorganisms. It provides the mathematical basis for the evaluation of the average relative performance of two quantitative methods against chosen criteria for the comparison. It does not provide data for assessment of the precision of the methods being compared. It is appropriate that the precision of methods is assessed as part of their performance characterization. ISO 17994:2014 does not provide methods for the verification of method performance characterization in a single laboratory.
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Sisällysluettelo
Foreword
Introduction
1 Scope
2 Normative references
3 Terms, definitions and symbols
3.1 Terms and definitions
3.2 Symbols and abbreviated terms
4 Principle
5 Basic requirements for a comparison study
5.1 General
5.2 Description of methods
5.3 Types of samples
5.4 Number of samples and participating laboratories
5.5 Counting and confirming
6 Calculations
6.1 Preliminary editing of the raw data
6.2 Basic relative differences
6.3 Half-width of the confidence interval
7 Evaluation
7.1 Preliminary evaluations
7.2 Two-sided evaluation
7.3 One-sided evaluation
8 Test report
Annex A Flowchart (informative)
Annex B Comparison studies (informative)
Annex C Derivation of equation for calculation of the number of samples (informative)
Annex D Example of a two-sided evaluation (informative)
ISO 8199:2005 Water quality -- General guidance on the enumeration of micro-organisms by culture
ISO/TR 13843:2000 Water quality -- Guidance on validation of microbiological methods
ISO 8199:2005 Water quality -- General guidance on the enumeration of micro-organisms by culture
ISO/TR 13843:2000 Water quality -- Guidance on validation of microbiological methods