Quality Assessments and Performance Evaluation

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Quality Assessments and Performance Evaluation

During the collection and analysis of environmental samples, scientists continually check for random and systematic errors by analyzing quality control samples. Blanks, duplicates and spiked samples are processed in the field and laboratory to monitor bias and imprecision in the data.

In addition to these internal quality control checks, several external, independent assessments of data quality are performed:

Laboratories analyze quality control samples of unknown concentration such as reference samples, blind audit samples and split samples. Results of these samples are evaluated by quality assurance staff to assess laboratory performance. Poor performance results often require followup and corrective action. For more information, see the Chesapeake Bay Split Sample and Blind Sample Programs site.
Chesapeake Bay Program staff conduct on-site audits of field, laboratory and data management procedures to ensure that staff are following their standard operating procedures.
Reported data undergo a final check before they are released. An automated computer program called Quality Assurance Tool performs up to 150 checks on water quality data sets as a final check on accuracy.

Documentation:

Procedures for Collecting Mainstem Split Samples (214 kb)
USGS Nutrient Reference Sample Results (1.6 MB)
Chesapeake Bay Program Mainstem Coordinated Split Sample Program Report, May 2001-May 2002 (1.2 MB)
Chesapeake Bay Program Blind Audit 2001 Final Report (198 kb)
Chesapeake Bay Program Blind Audit 2002 Final Report (98 kb)
Chesapeake Bay Program Blind Audit 2003 Final Report (91 kb)

Publications (CBP):

Recommended Guidelines for Sampling and Analyses in the Chesapeake Bay Monitoring Program, Chapter II (EPA-903-R-96-006) (1.4 MB)
Chesapeake Bay Program Mainstem Coordinated Split Sample Program Report,1994-1998 (EPA-903-R-99-024) (614 kb)

Other Sites of Interest:

The EPA Quality System - The EPA has developed a Quality System to manage the quality aspects of its environmental data collection, generation, and use.
U.S. EPA QA Plan Guidance - Agency-wide Quality System Documents.
USGS Reference Sample Program - Since 1962, the U.S. Geological Survey (USGS) has operated the Standard Reference Sample Project (SRSP).
EPA Region 3 Library - The Environmental Science Center (ESC) Library's mission is to support the information needs of EPA staff at the Environmental Science Center located at Fort George Meade, Maryland.

To bookmark this page, please use this URL: http://www.chesapeakebay.net/qaperformance.htm

For more information, contact the Chesapeake Bay Program Office:
410 Severn Avenue, Suite 109, Annapolis, MD 21403 / Tel: (800) YOUR-BAY / Fax: (410) 267-5777.