USGS - science for a changing world
Quality Systems Branch       

Stylish Drop Down Menu In HTML Css3Menu.com

  |  OBSP Home page |  Analytes |  Schedules |  Tools |  Summaries - Internal Only |  Raw Data - Internal Only |  Glossary |  Our Contacts

 

False Positive and False Negative Charts

The false positive and false negative results are summarized by schedule in a data table. The green line on the chart describes the analyte reporting level.

The false positive and false negative chart display all concentration results, and false positives are represented by a red asterisk and false negatives are represented by a red down arrow.

A list of false positives and false negatives below the chart summarizes the false positive and false negative results and provides expected concentration and result concentrations for every analyte for every schedule OBSP assesses.

A false positive result - when an analyte is reported by the laboratory when it is not present in the sample. False positives can result from random variability in background response, contamination, degradation of a parent product or misidentification of the analyte.

A false negative result - the analyte is present in the sample but it is not reported by the laboratory. False negatives can arise from random variability, lower than normally expected recovery, or misidentification of the analyte.

Note: If an analyte of interest is not seen in the method listing, there is no OBSP data available for that analyte




Most current False Positive and False Negative Charts
False Positive and False Negative charts for January 2007 to December 2012
False Positive and False Negative charts for January 2001 to September 2006

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://bqs.usgs.gov/index.php
Project Contact Information: dbeaty@usgs.gov
Page Contact Information: Webmaster
Page Last Modified: March 29, 2023