Day 2 DQO Training Course
Module 5
The EPA 7-Step DQO Process
Step 5 - Define Decision Rules
Presenter: Sebastian Tindall
(15 minutes)
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Step 5: Define Decision Rules
Step 1: State the Problem
Step 2: Identify Decisions
Step 3: Identify Inputs
Step 4: Specify Boundaries
Step 5: Define Decision Rules
Step 6: Specify Error Tolerances
Step 7: Optimize Sample Design
Step Objective:
 This step combines Steps
1 - 4 to produce the
following major elements
to form decision rules:
–
–
–
–
Parameter of interest
Unit of decision making
Action level
Alternative actions
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Step 5- Define Decision Rules
Information IN
Principal Study Question
From Previous Step
Step 2
Actions
Specify the Parameter of
Interest
Information OUT
To Next Step
Information Required to
Resolve Decision Statement
Step 3
Population of Interest
Step 4
Unit of Decision
Making
Develop a
Decision Rule
Step 4
Alternative Actions
Step 2
If/Then
Decision
Rule
Statements
Confirm the Action
Level
Basis for Defining
Action Level
Step 3
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute in the population
• Levels measured (Quantity)

Unit of Decision Making
– Geographic Area/Volume
– Timeframe
– Population


Action Level
Alternative Action(s)
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute in the population
descriptive
measure
(such as a true mean, median, or proportion)
•A Levels
measured
(Quantity)
that specifies the characteristic or attribute that the decision
 Unitmaker
of Decision
would like toMaking
know about the population. By definition,
this will always
remain unknown. Note: The purpose of any
– Geographic
Area/Volume
data collection design is to produce environmental data that
– Timeframe
can be used as a reasonable estimate of this population
parameter.
– Population


Action Level
Alternative Action(s)
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute in the population
• Levels measured (Quantity)

The sample statistic,
e.g., the sample mean, which is obtained
Unit of Decision
Making
from the sampling data is used to estimate the population
– Geographic
Area/Volume
parameter.
It is often the upper confidence limit about the
sample mean.
– Timeframe
– Population


Action Level
Alternative Action(s)
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Background
The variable
is both the COPC
(chemical and physical)
Major Elements
of a Decision
Rule:
and the level measured. Examples of the level are
 Parameterconcentration
of Interestor activity or result.
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute in the population
• Levels measured (Quantity)

Unit of Decision Making
– Geographic Area/Volume
– Timeframe
– Population


Action Level
Alternative Action(s)
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
–
–
–

Population Parameter
Sample
Statistic
The
smallest,
most appropriate subset
(sub-population)
which separate
Environmentalfor
Variable
decisions will be made.
• Chemical/Physical attribute in the population
• Levels measured (Quantity)
Unit of Decision Making
– Geographic Area/Volume
– Timeframe
– Population


Action Level
Alternative Action(s)
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute in the population
Spatial Boundary
• Levels measured (Quantity)

Unit of Decision Making
– Geographic Area/Volume
– Timeframe
– Population


Action Level
Alternative Action(s)
Temporal Boundary
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute in the population
• Levels measured (Quantity)

Unit of Decision Making
– Geographic Area/Volume
– Timeframe
The total number of objects
(samples of soil or sludge or
– Population


Action Level
Alternative Action(s)
sediment or air, etc.), that are
contained within the spatial
unit to be studied
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
– Environmental Variable
• Chemical/Physical attribute
in the population
A measurement
threshold value of
• Levels measured (Quantity)
the parameter of interest that
provides the criterion for choosing
 Unit of Decision Making
among alternative actions.
– Geographic Area/Volume
– Timeframe
– Population


Action Level
Alternative Action(s)
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Background
Major Elements of a Decision Rule:
 Parameter of Interest
– Population Parameter
– Sample Statistic
actions that the decision maker would
– Environmental The
Variable
take attribute
depending
value of the sample
• Chemical/Physical
in on
thethe
population
statistic which is an estimate of the
• Levels measured (Quantity)
population parameter.

Unit of Decision Making
– Geographic Area/Volume
– Timeframe
– Population


Action Level
Alternative Action(s)
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Step 5- Define Decision Rules
Information IN
Principal Study Question
From Previous Step
Step 2
Actions
Specify the Parameter of
Interest
Information OUT
To Next Step
Information Required to
Resolve Decision Statement
Step 3
The purpose of the data collection design is to produce
Population of environmental
Interest
data that can be used as a reasonable estimate
Step 4 of the population (true) parameter.
If/Then
Decision
Develop a
Unit of Decision
Rule
Decision Rule
Making
Statements
Step 4
Alternative Actions
Step 2
Confirm the Action
Level
Basis for Defining
Action Level
Step 3
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Step 5- Define Decision Rules
Information IN
Principal Study Question
From Previous Step
Step 2
Actions
Specify the Parameter of
Interest
Information OUT
To Next Step
Information Required to
Resolve Decision Statement
If Step
not3done in Step 3, specify the numerical value that would
cause a person to choose between alternative actions.
Population of Interest
Step 4
Confirm that the action level is greater than the detection/
Develop a methods
Unitquantitation
of Decision limits for the potential measurement
Decision Rule
identified
Making in Step 3.
Step 4
Alternative Actions
Step 2
If/Then
Decision
Rule
Statements
Confirm the Action
Level
Basis for Defining
Action Level
Step 3
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Step 5- Define Decision Rules
Information IN
Principal Study Question
From Previous Step
Step 2
Actions
Specify the Parameter of
Interest
Information OUT
To Next Step
Information
Required
to rule as an “if…then…” statement that incorporates the
Develop
a decision
Resolve
Decision Statement
parameter
of interest, the unit of decision making, the action level, and the
Step 3 that would result from resolution of the decision.
action(s)
Population of Interest
Step 4
Unit of Decision
Making
Develop a
Decision Rule
Step 4
Alternative Actions
Step 2
If/Then
Decision
Rule
Statements
Confirm the Action
Level
Basis for Defining
Action Level
Step 3
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Decision Rule

General Format
If the [parameter of interest (4 elements)]
within the [unit of decision (3 elements)] is >
the [action level], then take [alternative
action A]; or take [alternative action B].
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Decision Rule Example 1
If the [“true” mean (as estimated by the 95%
UCL of the sample mean) concentration of
U-238] within the [surface soil in the
perimeter of the backyard to a depth of 6
inches] is > [20 pCi/g], then [dispose of soil in a
radiological landfill]; or [leave the soil in place].
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Decision Rule Example 2
If the [“true” mean (as estimated by the one
sided 90% UCL of the sample mean)
concentration of cadmium] within [the metal
turnings in a 55 gallon drum] is > [1 mg/kg],
then [the metal turnings will be considered
hazardous and will be disposed of in a RCRA
facility]; or [the metal turnings will be
disposed of in a municipal landfill].
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“Typical” Decision Rules

If the vadose zone soil moisture content, contaminant concentration
profiles, and soil physical properties from the 1454 site exceed or
deviate significantly from the conceptual model, an additional
evaluation will be performed to assess priority of performing further
analysis.

The data gathered from the characterization boring located at the
1454 site combined with historical process data and geophysical
logging (high resolution spectral gamma-ray and neutron logging)
of existing wells located in the vicinity of the 1455 site can be used
to create an analogous model for the 1455 site. If the data collected
from characterization of the 1454 site and the geophysical logging
data from the existing wells located near the 1455 site support the
conceptual model, the analogous unit approach is valid for the 1455
site.
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CS
Step 5- Decision Rules
DS
#
Population
Parameter
Sampl e
Stati stics
Environmental
Va riable
Attri bute
Unit or Scale of
Decision Making
Re lation sh ip
Action
Level(a)
A A #1
Re lation sh ip
AA #2
Unit of
Measure
If the true
mean
concentration
as estimated
by 95% UCL
of the sample
mean
of the lead, measured
in mg/kg
Within the foot print
and run-off area
from 0” to 6” depth
If the true
mean
concentration
as estimated
by 95% UCL
of the sample
mean
of the uranium,
measured in mg/kg
Within the foot print
and run-off area
from 0” to 6” depth
If the true
mean
concentration
as estimated
by 95% UCL
of the sample
mean
of the TPH, measured
in mg/kg
Within the foot print
and run-off area
from 0” to 6” depth
If the true
mean
concentration
as estimated
by 95% UCL
of the sample
mean
of the PCBs, measured
in mg/kg
Within the foot print
and run-off area
from 0” to 6” depth
then
Is greater than
 250 mg/kg
Lead
then
Is greater than
 240 mg/kg
Uranium
then
Is greater than
 100 mg/kg
TPH
 1 mg/kg
PCBs (total
Aroclors)
then
conduct
remedial
action
conduct
remedial
action
or
take no
further
action is
required
or
take no
further
action is
required
or
take no
further
action is
required
or
take no
further
action is
required
1
a
Is greater than
conduct
remedial
action
conduct
remedial
action
State Regulations (which are the same or more restrictive that federal regulations). State Regulations 173-4901 also typically specify the required assumptions for
risk assessment and specify the degree of site specific information required.
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Decision Rule 1a
CS
If the true mean (as estimated by the 95% UCL
of the sample mean) concentration of the
contaminant within the surface soil to a depth of
6 inches of the Pad footprint and run-off zone is
> the AL, then conduct remedial action; or take
no further action.
Contaminates/Action Limits
• 250 mg/kg Lead
• 240 mg/kg Uranium
• 100 mg/kg TPH
• 1 mg/kg PCBs (total Aroclors)
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Decision Rule 1b
CS
If the true mean (as estimated by the 95% UCL
of the sample mean) concentration of the
contaminant within the surface soil to a depth of
6 inches of the radial buffer zone excluding the
Pad and run-off zone is > the AL, then conduct
remedial action; or take no further action.
Contaminates/Action Limits
• 250 mg/kg Lead
• 240 mg/kg Uranium
• 100 mg/kg TPH
• 1 mg/kg PCBs (total Aroclors)
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CS
Decision Rule 2a
If the true mean (as estimated by the 95% UCL
of the sample mean) concentration of the
contaminant within the subsurface soil to a
depth of 6” to 10’ of the Pad footprint and runoff zone is > the AL, then conduct remedial
action; or take no further action.
Contaminates/Action Limits
• 250 mg/kg Lead
• 240 mg/kg Uranium
• 100 mg/kg TPH
• 1 mg/kg PCBs (total Aroclors)
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Decision Rule 2b
CS
If the true mean (as estimated by the 95% UCL
of the sample mean) concentration of the
contaminant within the surface soil to a depth of
6” to 10’ of the radial buffer zone excluding the
Pad and run-off zone is > the AL, then conduct
remedial action; or take no further action.
Contaminates/Action Limits
• 250 mg/kg Lead
• 240 mg/kg Uranium
• 100 mg/kg TPH
• 1 mg/kg PCBs (total Aroclors)
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Step 5 - Summary
After data are obtained and undergo Data
Quality Assessment, decision rules are used
to make the decisions
 The decision rules encompass the logic used
and include inputs from Steps 1-4 and 6
 One may need to perform Step 6 and then
update Step 5 to include the statistical
decision criteria

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Step 5- Define Decision Rules
Information IN
Principal Study Question
From Previous Step
Step 2
Actions
Specify the Parameter of
Interest
Information OUT
To Next Step
Information Required to
Resolve Decision Statement
Step 3
Population of Interest
Step 4
Unit of Decision
Making
Develop a
Decision Rule
Step 4
Alternative Actions
Step 2
If/Then
Decision
Rule
Statements
Confirm the Action
Level
Basis for Defining
Action Level
Step 3
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End of Module 5
Thank you
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