Data Quality Objectives
Entech Engineering's Data Quality Objectives (DQOs) are guidelines for obtaining quality data that are representative and indicative of the source tested. The DQOs are accomplished in terms of precision, accuracy, completeness, comparability, representativeness, and Practical Quantitation Limits (PQLs). The procedures prescribed here are intended to ensure that the adequate DQOs are set and achieved.
Precision - Precision is a measure of the agreement among individual measurements of the same parameter performed under similar conditions. It shows the extent of inherent variability in sampling and analytical procedures. Sampling precision is evaluated using field sample / field sample duplicate (FS / FSD) pairs. Analytical precision can be evaluated using matrix spike / matrix duplicate (MS / MSD) pairs.
Accuracy - Accuracy is a measure of how closely measured values agree with the true value of a parameter. Accuracies are evaluated using sample probe standards for analysis and standard blanks to determine the extent of sample contamination. The DQO for relative percent difference (RPD) between results of duplicate pair analyses is usually specified.
- Completeness - Completeness is a measure of information collected from a sampling and analysis episode compared with information desired to be produced. The DQO on completeness for each episode is 100%. If completeness for any sampling and analysis episode is less than 100%, the circumstances are documented and the impact on data quality is evaluated. Additional testing and / or monitoring may be requested as a supplement.
Comparability - Comparability is the measure of the degree of confidence of one data set compared with another. Comparability is assured by using the same monitoring procedures for each sampling episode at the facility. Analytical data will be reported in the same manner and units for each test.
Representativeness - Representativeness is a measure of the degree to which the monitoring results represent the population from which the sample was obtained. Representativeness will be assured by following prescribed procedures.
Practical Quantitation Limits (PQLs) -The PQLs for target analyses using the proposed test procedures will be determined by Entech Engineering prior to each project. The PQLs for target parameters will be equal to or less than those listed in the methods. In instances where the PQL may not meet the need of the program, Entech Engineering will identify that situation and recommend either an approach to alleviate the situation or an alternate procedure with a more appropriate PQL.
Copyright © 2008 - 2012 Entech Engineering Inc. All Rights Reserved.