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AWWA WQTC71481
- Statistical Consideration for Validating a New Microbial Analysis Method
- Conference Proceeding by American Water Works Association, 11/01/2009
- Publisher: AWWA
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This paper presents a case study for the validation of a new method for detecting coliphage in groundwater samples. Coliphage is one of the microbial indicators that can be used to monitor fecalcontamination under the Ground Water Rule. This paper describes the statistical considerations required in the design of a validation study for the alternative test procedure (ATP) and performance based measurements system (PBMS) approaches. The paper evaluates the number of comparisons necessary to demonstrate equivalence or acceptability by the two approaches. Results of validation were used to demonstrate the relationship between sample size and the confidence intervals around recoveries, sensitivity (true positives), specificity (true negatives), false positives andfalse negatives between methods. This was contrasted with the relationship between sample size andthe ability to detect differences between methods using the ATP method. The design and results of aninter-laboratory validation study are presented, focusing on the sample sizes required and thedifferences that can be detected between laboratories. Includes 2 references, tables, figures.