Purpose and Goals

The DQO Process is a strategic planning approach based on the Scientific Method to prepare for a data collection activity.  It provides a systematic procedure for defining the criteria that a data collection design should satisfy, including when to collect samples, where to collect samples, the tolerable level of decision error for the study, and how many samples to collect, balancing risk and cost in an acceptable manner.

Using the DQO Process will assure that the type, quantity, and quality of environmental data used in decision making will be appropriate for the intended application, resulting in environmental decisions that are technically and scientifically sound and legally defensible.  In addition, the DQO Process will guard against committing resources to data collection efforts that do not support a defensible decision.

What are DQOs?  DQOs are qualitative and quantitative statements derived from the outputs of the first six steps of the DQO Process that:
 

1. Clarify the study objective;
2. Define the most appropriate type of data to collect;
3. Determine the most appropriate conditions from which to collect the data; and
4. Specify tolerable limits on decision errors which will be used as the basis for establishing the quantity and quality of data needed to support the decision.

The DQOs are then used to develop a scientific and resource-effective data collection design.

By using the DQO Process, decision makers are assured that the type, quantity, and quality of environmental data appropriate for the intended application.  In addition, decision makers will guard against committing resources to data collection efforts that do not support a defensible decision.

Each of the seven steps is described briefly below.  A more detailed description can be found in the subsequent chapters of this guidance (EPA 1994, EPA 2000a and EPA 2000b).
 

• Step 1:  State the Problem

• Concisely describe the problem to be studied.  Review prior studies and existing information to gain a sufficient understanding to define the problem.
   

• Step 2:  Identify the Decision

• Identify the Principle Study Questions that need to be answered and what actions may result, in order to resolve the Problem Statement..
   

• Step 3:  Identify the Inputs to the Decision

• Identify the information and envoironmental measurements that are needed to resolve the Principle Study Questions.
   

• Step 4:  Define the Study Boundaries

• Specify the time periods and spatial area to which decisions will apply.  Determine when and where data should be collected.
   

• Step 5:  Develop a Decision Rule

• For each Principle Study Question, define the statistical parameter of interest, specify action levels, and integrate the previous DQO outputs into "if...then" statements that describes the logical basis for choosing among alternative actions.
   

• Step 6:  Specify Tolerable Limits on Decision Errors

• Define the decision maker's tolerable decision error rates¹ based on the consequences of making an incorrect decision.
   

• Step 7:  Optimize the Design

• Evaluate information from the previous steps and generate alternative data collection designs.  Choose the most resource-effective design that meets all DQOs.
   

¹ A decision error rate is the probability of making an incorrect decision based on data that inaccurately estimate the true state of nature.

References:
 

• EPA 1994a: Guidance for the Data Quality Objectives Process, EPA QA/G-4, U.S. EPA, Quality Assurance Management Staff, Washington, D.C. 20460; Final, September 1994; [pdf]

• EPA 2000a: Guidance for the Data Quality Objectives Process; Office of Environmental Information, U.S. EPA, Washington D.C. 20460; August 2000) [pdf]
  
  
• EPA 2000b: Data Quality Objectives Process for Hazardous Waste Site Investigations; Office of Environmental Information, U.S. EPA, Washington D.C. 20460; January 2000) [pdf]
  

• U.S. EPA Office of Inspector General, Report of Audit: Laboratory Data Quality at Federal Facility Superfund Sites, E1SKB6-09-0041-71001.32, March 20, 1997;

• Bechtel Hanford Inc. Procedure: BHI-EE-01, Environmental Investigations Procedure: Data Quality Objectives; Procedure Number 1.2; Revision 3; September 30, 1999; [pdf]

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DOE DQO Program Manager, Dr Jeffrey W Day, (509) 372-4629.
WCH DQO Coordinator, Sebastian Tindall, (509) 845-7078.

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