Document ID: EPA-HQ-OEI-2009-0795-0006
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-11-17T05:00Z

DRAFT

QUALITY ASSURANCE

and QUALITY CONTROL

DATA STANDARD

Standard No.: EX000012.2

July 10, 2009

	

This standard has been produced through the

Exchange Network Leadership Council (ENLC).

The Exchange Network Leadership Council (ENLC) is a partnership among US
EPA, States and Tribal partners to promote the efficient sharing of
environmental information through the efficient management of the
Exchange Network development and adoption of data standards. More
information about is available at www.exchangenetwork.net/standards 
HYPERLINK "http://"   .

Foreword

The Exchange Network Leadership Council (ENLC) is a partnership among US
EPA, States and Tribal partners to develop and agree upon data standards
for environmental information collection and exchange.  The Council
seeks to promote efficient sharing of environmental information between
State, US EPA and Tribal partners through the development of data
standards.  More information about data standards is available at
http://www.exchangenetwork.net/standards.

1.0	INTRODUCTION

Environmental information is a key tool in the effective management of
our environmental resources and human health conditions.  As a result,
much effort goes into data acquisition, management, maintenance,
exchange, and oversight.  Greater access is the goal of many data
consumers, and data managers. Providers invest significant resources
meeting their requirements. In response, many data providers are
improving access as they post usable copies of their environmental
information on the web.  These efforts are a vast improvement over
previous conditions; however, there is a growing desire and need to both
provide and receive data in a clearly defined and a uniform way.  Data
from multiple sources can then be aggregated and used without the
inherent variations that exist between data sets across agencies. 

1.1	Scope

This standard provides data elements and describes quantitative
statistics and qualitative descriptors that are used to interpret the
degree of acceptability or utility of data to the user.   

1.2	Revision History

Date	Version	Description

January 6, 2006	EX000012.1	Initial Environmental Data Standards Council
Adoption

July 22, 2008	EX000012.2	Modification of data standard to incorporate
additional water quality and biological related data elements. 

1.3	References to Other Data Standards

None.



1.4	Terms and Definitions

For the purposes of this document, the following terms and definitions
apply.

Term	Definition

Quality Assurance (QA)	The system implemented by an organization which
assures outside bodies that the data generated is of proven and known
quality and meets the needs of the end user.  This assurance relies
heavily on documentation of processes, procedures, capabilities, and
monitoring of such.  

Quality Control (QC)	Those operations undertaken in the laboratory or
field to ensure that the data produced are within known measures of
accuracy and precision.  These operations may include calibration,
method blanks, matrix spikes, blank spikes, surrogates, duplicates,
system checks, as well as others.  

1.5	Implementation

Users are encouraged to use the XML registry housed on the Exchange
Network Web site to download schema components for the construction of
XML schema flows (  HYPERLINK "http://www.exchangenetwork.net" 
http://www.exchangenetwork.net ).  

1.6	Document Structure

The structure of this document is briefly described below:

Section 2.0 Quality Assurance and Quality Control Diagram, illustrates
the principal data groupings contained within this standard.  

Section 3.0 Quality Assurance and Quality Control Data Standard Table,
provides information on the high level, intermediate and elemental
Quality Control and Quality Assurance data groupings.  Where applicable,
for each level of this data standard a definition, XML tag, note(s),
example list of values and format are provided. The format column may
include the number of characters for the associated data element, where
“A” specifies alphanumeric, “N” designates numeric, and “G”
and “D” are used for grouping and date respectively. 

Data Element Numbering. For purposes of clarity and to enhance
understanding of data standard hierarchy and relationships, each data
group is numerically classified from the primary to the elemental level.

Code and Identifier Metadata: Metadata, defined here as data about data
or data elements, includes their descriptions and/or any needed context
setting information required to identify the origin, conditions of use,
interpretation, or understanding  the information being exchanged or
transferred.  (Adapted from ISO/IEC 2382-17:1999 Information Technology
Vocabulary—Part 17: Databases 17.06.05 metadata).  Based on the
business need, additional metadata may be required to sufficiently
describe an identifier or a code. A note regarding this additional
metadata is included in the notes column for identifier and code
elements. Additional metadata for identifiers may include:

Code List Identifier, which is a standardized reference to the context
or source of the set of codes

Additional metadata for codes may include: 

Code List Identifier, which is a standardized reference to the context
or source of the set of codes

Code List Version Identifier, which identifies the particular version of
the set of codes.

Code List Version Agency Identifier, which identifies the agency
responsible for maintaining the set of codes

Code List Name, which describes the corresponding name for which the
code represents

Appendix A, Quality Assurance and Quality Control Data Standard
Structure Diagram illustrates the hierarchical classification of the
QA/QC data standard. This diagram enables business and technical users
of this standard to quickly understand its general content and
complexity. Appendix B, lists the references for the Quality Assurance
and Quality Control Data Standard.

2.0	QUALITY ASSURANCE AND QUALITY CONTROL DATA STANDARD DIAGRAM

This diagram specifies the major data groups that may be used to
identify the characteristics and/or to catalog quality assurance and
quality control.  

	     

	  3.0 	QUALITY ASSURANCE AND QUALITY CONTOL DATA STANDARD TABLE

1.0	Data Quality Indicator 

Definition: 	The quantitative statistics and qualitative descriptors
that are used to interpret the degree of acceptability or utility of 		
data to the user.

	Relationships:  None. 

Notes:		None.

XML Tag: 	DataQualityIndicator

Data Element Name	Data Element Definitions	Notes	Format 	XML Tags

1.1 Precision Value	A measure of mutual agreement among individual
measurements of the same property usually under prescribed similar
conditions.  	Note: This measure is the random component of error. 

Example: Relative Percent Difference (RPD or di), where X is the primary
value and Y is the duplicate:

 	N	PrecisionValue

1.2 Precision Type Text	Classifies the type of precision measurement as
either intratest or intertest.	Permissible Values List: 

Intratest

Intertest	A	PrecisionTypeText

1.3 Bias Value	The systematic or persistent distortion of a measurement
process which causes error in one direction. 	Note: Bias will be
determined by estimating the positive and negative deviation from the
true value as a percentage of the true value.

Example: Percent Difference, where X is the known or spiked amount, and
Y is the measured concentration:

 	N	BiasValue

1.4 Confidence Interval Value	A range of values constructed so that this
range has a specified probability of including the true population mean.
 	Note: This range is symmetric about the sample mean, the specified
probability is called the confidence level, and the end points of the
confidence interval are called the upper and lower confidence limits.

Confidence limit may be calculated as:

     

	N	ConfidenceIntervalValue

1.5 Upper Confidence Limit Value	Value of the upper end of the
confidence interval.	See 1.3 Confidence Interval	N
UpperConfidenceLimitValue

1.6 Lower Confidence Limit Value 	Value of the lower end of the
confidence interval.	See 1.3 Confidence Interval	N
LowerConfidenceLimitValue



Appendix A

Quality Assurance and Quality Control Data Standard Structure Diagram



Appendix B

References

ISO/IEC 2382-17:1999 Information Technology Vocabulary—Part 17:
Databases 17.06.

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	Quality Assurance and Quality Control Data Standard

Std No.: 1-XXX

Version 1.0 – Final Draft

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Quality Assurance and Quality Control Data Standard

Std No.: EX000012.2

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Quality Assurance and Quality Control              Data standard

 

Data Standard

Data Quality 

Indicator

Quality Assurance and Quality Control Data Standard

Data Quality Indicator 

1.1	Precision Value

1.2    Precision Type Text

1.3    Bias Value

1.4    Confidence Interval Value

1.5    Upper Confidence Limit Value

1.6    Lower Confidence Limit Value