QA - Duplicate
--------------

Precision refers to the agreement between independent measurements performed according to identical protocols and procedures. Collocated monitoring, analysis of duplicate samples and analysis of replicate samples are ways to estimate precision for all or part of the measurement system. In order to distinguish these terms, the following definitions come from the NATTS Technical Assistance Document (available on EPA's AMTIC website). These definitions will apply for data submitted to AQS using the duplicate or replicate transaction.

*  Collocated Sample Collection - Collocated samples are samples collected simultaneously using two completely separate sampling systems, and then analyzing the samples and comparing the results obtained. This approach provides information on "Inter-system" variability.
*  Duplicate Sample Collection - Duplicate samples are samples collected simultaneously using one collection system (i.e., two separate samples through the same sampling system at the same time), and then analyzing the samples and comparing the results obtained. This simultaneous collection is typically accomplished by teeing the line from the flow control device to the canisters, and then doubling the collection flow rate. This approach provides information on "Intra-system" variability.
*  Replicate Analysis - Replicate analyses is the analysis of one discrete sample multiple times. These are also known as "split" sample analyses. This approach provides information on "Analytical" variability.




Format
^^^^^^

.. list-table:: QA - Duplicate transaction format
   :widths: 1 5 15 4 3 1
   :header-rows: 1


   * - Seq.
     - Name
     - Description
     - Formatting Rules
     - Required
     - Key
   * - 1
     - `Transaction Type <Transaction%20Type.html>`_
     - Quality Assurance transaction identifier.
     - Must = QA
     - Always
     - 
   * - 2
     - `Action Indicator <Action%20Indicator%20for%20Transaction.html>`_
     - Indicator for Insert, Update, or Delete action.
     - Must = I, U, or D
     - Always
     - 
   * - 3
     - `Assessment Type <Assessment%20Type.html>`_
     - Indicates the specific QA assessment associated with the transaction.
     - Must = Duplicate
     - Always
     - Y
   * - 4
     - `Performing Agency <Performing%20Agency.html>`_
     - Agency Code of organization performing assessment.
     - Must exist in AGENCIES reference table.
     - Optional; defaults to user agency
     - 
   * - 5
     - `State Code / Tribal Indicator <State%20Code.html>`_
     - The FIPS state code of the monitor, or "TT" to indicate that the next field on the transaction is a Tribal code.
     - Must exist in STATES Reference Table or be 'TT' for Tribal Site
     - Always
     - Y
   * - 6
     - `County Code / Tribal Code <County%20Code.html>`_
     - The FIPS County Code of the site.  If the previous field on the transaction contains "TT", then the Tribal Code of the site.
     - Must exist in COUNTIES (for state) or TRIBAL_AREAS Reference table
     - Always
     - Y
   * - 7
     - `Site Number <Site%20Number.html>`_
     - Four digit number to uniquely identify site in county and/or tribe.
     - Must exist in SITES table with {State Code, county Code} or Tribal Code
     - Always
     - Y
   * - 8
     - `Parameter Code <Parameter%20Code.html>`_
     - The AQS parameter code assigned to the monitor in AQS.
     - Must exist in PARAMETERS reference table.
     - Always
     - Y
   * - 9
     - `POC <POC.html>`_
     - Parameter Occurrence Code:  One or two digit number identifying a specific monitor for a parameter at the site.  
     - Must exist in MONITOR table for non-Insert actions.
     - Always
     - Y
   * - 10
     - `Assessment Date <Assessment%20Date.html>`_
     - Date that the assessment was performed
     - YYYYMMDD.
     - Always
     - Y
   * - 11
     - `Assessment Number <Assessment%20Number.html>`_
     - A unique number associated with an assessment performed at a site on a given day.  Value should be "1" unless additional same assessments are performed.  
     - Integer.
     - Always
     - Y
   * - 12
     - `Monitor Method Code <Monitor%20Method%20Code.html>`_
     - The sampling methodology of the monitor being assessed.
     - Must exist in SAMPLING METHODOLOGIES reference table.
     - Insert
     - 
   * - 13
     - `Reported Unit <Reported%20Unit.html>`_
     - Units associated with the assessment.
     - Must exist in UNITS reference table, and unit code must be for Concentration units type.
     - Unless Delete
     - 
   * - 14
     - `Duplicate Value 1 <Duplicate%20Value%201-5.html>`_
     - The concentration value provided by the monitor being assessed.  
     - Decimal.
     - Insert
     - 
   * - 15
     - `Duplicate Value 2 <Duplicate%20Value%201-5.html>`_
     - The concentration value provided by the monitor being assessed.  
     - Decimal.
     - Insert
     - 
   * - 16
     - `Duplicate Value 3 <Duplicate%20Value%201-5.html>`_
     - The concentration value provided by the monitor being assessed.  
     - Decimal.
     - Insert
     - 
   * - 17
     - `Duplicate Value 4 <Duplicate%20Value%201-5.html>`_
     - The concentration value provided by the monitor being assessed.  
     - Decimal.
     - Insert
     - 
   * - 18
     - `Duplicate Value 5 <Duplicate%20Value%201-5.html>`_
     - The concentration value provided by the monitor being assessed.  
     - Decimal.
     - Insert
     -