<simpleType name="QualifierEnumType">
  <annotation>
    <documentation>Qualifiers on a reported value: whether it is exact, an average, a limit, a non-detect or a result with known bias.</documentation>
  </annotation>
  <restriction base="string">
    <enumeration value="exact">
      <annotation>
        <documentation>The value is exact. This is the default condition unless other qualifier values are given.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="average">
      <annotation>
        <documentation>The value is an average of measurements over a time or distance interval.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="less than">
      <annotation>
        <documentation>The value is below a stated threshold. Used where an analyte was not detected or was below the threshold: if 3.6 is the limit, the result is somewhere below it.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="greater than">
      <annotation>
        <documentation>The true value exceeds the reporting or calibration range.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="non-detect">
      <annotation>
        <documentation>Specifically for instrumental "not detected" results where no signal was distinguishable from noise.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="saturated">
      <annotation>
        <documentation>The instrument sensor was overloaded (saturated) by the signal, meaning the reported value is the maximum "clipped" output and the true value is likely much higher.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="limit of detection">
      <annotation>
        <documentation>The lowest value that can be identified with 99% confidence as being greater than zero.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="low bias">
      <annotation>
        <documentation>The result is likely an underestimate of the true value due to known systematic error (e.g., sample loss).</documentation>
      </annotation>
    </enumeration>
    <enumeration value="high bias">
      <annotation>
        <documentation>The result is likely an overestimate (e.g., due to contamination or interference).</documentation>
      </annotation>
    </enumeration>
  </restriction>
</simpleType>