LEP Project Chief: (vacant).   For questions, contact James Simmons (jsimmons@usgs.gov)
U.S. Geological Survey
Denver Federal Center
Mail Stop 401, Box 25046
Denver, CO 80225

Laboratory Evaluation Project

Click here for access to internal (USGS users only) Laboratory Evaluation Project site.

The Laboratory Evaluation Project (LEP) provides technical support for compliance with the USGS Water Mission Area (WMA) policy that addresses laboratory evaluation by laboratory users. The USGS Survey Manual requires the documentation of data quality and is the basis for this policy.

All analytical laboratories used by WMA-supported projects and programs must provide appropriate supporting performance data to enable laboratory users to assess the quality of associated environmental-sample results. Laboratory performance data include:

 • Results from independent performance-test (PT) studies for the analytes of interest

  o External blind-sample programs or interlaboratory comparisons
  o Samples analyzed at least twice each year
  o Results need to include analysis date and expected value, in addition to laboratory measured value
  o Not available for all analytes and all sample types

 • Internal (laboratory) quality-control (QC) data and information to evaluate accuracy and other performance measures

  o Directly corresponding set- or run-specific QC-sample data
  o Can be used only if the QC-sample results are not used by the laboratory to adjust environmental-sample results
  o Need to include expected value for non-blank QC samples to show relevance to environmental data
  o Helpful to WMA laboratory users to receive a 6-month or 12-month spreadsheet compilation of internal QC data in addition to batch-QC data reported in data packages with sample results.
  o Helpful to WMA laboratory users to receive laboratory control (acceptance) limits for each laboratory QC-sample type.

Other laboratory information that is helpful to WMA laboratory users for laboratory evaluation:

 • Laboratory-method information

  o Method description (including method validation) or published-method reference
  o Detection limits and reporting limits (types and values)
  o Sample-dilution criteria or other sample-modification criteria

 • Brief description of laboratory internal data-review procedures

 • Definition (or reference for definition) of value remark or qualifier codes used

 • Laboratory control charts

Where performance data are available and relevant to the project, laboratory users should review and document the performance data. Where insufficient performance data are available for the laboratory, laboratory users must obtain relevant performance information by submitting performance-test samples or by ensuring that the laboratory participates in appropriate interlaboratory comparisons or analyzes appropriate internal QC samples. Review of performance data by laboratory users is critical to understanding the environmental-sample results, and in some cases, identifying biases or trends in laboratory performance that should not be attributed to the environment.

Click here for access to internal (USGS users only) Laboratory Evaluation Project site.



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