QA - Replicate

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

QA - Replicate transaction format

Seq.

Name

Description

Formatting Rules

Required

Key

1

Transaction Type

Quality Assurance transaction identifier.

Must = QA

Always

2

Action Indicator

Indicator for Insert, Update, or Delete action.

Must = I, U, or D

Always

3

Assessment Type

Indicates the specific QA assessment associated with the transaction.

Must = Replicate

Always

Y

4

Performing Agency

Agency Code of organization performing assessment.

Must exist in AGENCIES reference table.

Optional; defaults to user agency

5

State Code / Tribal Indicator

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

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

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

The AQS parameter code assigned to the monitor in AQS.

Must exist in PARAMETERS reference table.

Always

Y

9

POC

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

Date that the assessment was performed

YYYYMMDD.

Always

Y

11

Assessment Number

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

The sampling methodology of the monitor being assessed.

Must exist in SAMPLING METHODOLOGIES reference table.

Insert

13

Reported Unit

Units associated with the assessment.

Must exist in UNITS reference table, and unit code must be for Concentration units type.

Unless Delete

14

Replicate Value 1

The concentration value provided by the monitor being assessed.

Decimal.

Insert

15

Replicate Value 2

The concentration value provided by the monitor being assessed.

Decimal.

Insert

16

Replicate Value 3

The concentration value provided by the monitor being assessed.

Decimal.

Insert

17

Replicate Value 4

The concentration value provided by the monitor being assessed.

Decimal.

Insert

18

Replicate Value 5

The concentration value provided by the monitor being assessed.

Decimal.

Insert