November 14, 2012 Abt Associates | Economic and Financial Data Sanitation Plan | pg 1

Date November 14, 2012

To James Covington (EPA/OST/EAD)

From Isabelle Morin and Rob Chew

Subject Economic and Financial Data Sanitation Plan: Steam Electric Effluent Guidelines 

Rulemaking

This memorandum describes the proposed methodology for removing Confidential Business Information 

(CBI) data from Part I (Economic and Financial Data) of the Questionnaire for the Steam Electric Power 

Generating Effluent Guidelines. The objective of this process is to provide a version of the questionnaire 

responses that is informative and useful for public comment without releasing proprietary information. 

This memorandum details Abt Associates‟ approach to sanitizing the data, pending the approval of EPA‟s 

Engineering and Analysis Division (EAD).

Abt Associates will produce a sanitized version of the Part I Questionnaire responses in the form of an 

MS AccessTM database [Steam Electric Economic/Financial Questionnaire Database]. This database will 

be based on the final version of the record used for the Regulatory Impact Analysis for Proposed Effluent 

Limitations Guidelines and Standards for the Steam Electric Power Generating Point Source Category. 

This version will have CBI and CBI-deducible1responses redacted and will be included in the public 

docket.

Abt Associates will develop the public version of the Steam Electric Economic/Financial Questionnaire 

Database using the following steps:

Removing data with CBI claims

 Convert survey responses to a text format. This allows responses of all data types (Number, 

„Yes/No‟, and Text) to be processed consistently. 

 Develop, execute, and verify update queries to replace CBI data elements with the word “CBI”. This 

replacement step applies to every part of a multipart question that was tagged as CBI by the survey 

respondent.

Removing CBI-deducible data 

 To prevent the discovery of CBI data through financial statement analysis, we will identify survey

responses in which the balance sheet, income statement, or cash flow statement of the Immediate 

Parent firm is CBI. 

o In cases where CBI was claimed for at least one financial statement component, we will 

perform an update query to replace all financial statement data elements with the word 

“CBI”. This replacement step applies to every part of a multipart question that is tagged as 

CBI.

 

1 CBI-deducible data is information that can be combined with non-CBI data to determine (or back calculate) CBI information.

Memorandum

Environment and Resources
November 14, 2012 Abt Associates | Economic and Financial Data Sanitation Plan | pg 2

 In cases where a parent firm claims ownership of multiple steam electric facilities, we will ensure that 

parent firm CBI designations are consistent across survey responses. This will prevent parent firm 

data from being designated as CBI in one survey response and not in others.

- For example, suppose the company “Big Firm” owns two facilities, both of which responded

to the Steam Electric Questionnaire. At one facility, the survey respondent marks “Big 

Firm‟s” Total Revenue as CBI whereas at the other facility, “Big Firm‟s” Total Revenue is 

deemed to be non-confidential. To be conservative in our disclosure of economic and 

financial data, we would treat “Big Firm‟s” Total Revenue as CBI in both cases.

- We will develop, execute, and verify queries to identify where parent firm data is inconsistent 

across survey responses and replace inconsistent data elements with the word “CBI”. This 

replacement step applies to every part of a multipart question that is tagged as CBI.

- This procedure will be performed for both Immediate Parent and Ultimate Parent firm 

information.

 Occasionally, the ultimate parent firm is the same as the immediate parent firm. In these situations, 

we will identify cases where the respondent designated CBI differently in the ultimate parent firm and 

immediate parent firm sections.

- We will develop, execute, and verify update queries to replace ultimate or immediate parent 

data elements that differ between sections with the word “CBI”. This replacement step 

applies to every part of a multipart question that is tagged as CBI.

 To ensure the robustness of the survey responses, redundancies were built into Part I of the 

Questionnaire for certain key fields with related data elements (e.g., total revenue, revenue from 

electricity generation). If in the survey entry in a key field is designated as CBI, we will maintain the 

CBI designation for each instance in which the key value is reported.

- We will develop, execute, and verify update queries to replace key value data elements that 

are CBI with the word “CBI”. 

- All key fields relate to the Primary Immediate Parent firm. They include:

 “Total Revenue („000$)”

 “Total Electricity Uses/Sources (MWh)”

 “Revenue from Electricity Generation („000$)”

 For some survey responses that ask for numerical values, estimates of the values can be calculated 

from other information in the survey. In these cases where the numerical value is CBI and the value 

can be deduced from other information, we will redact the data that is necessary for the calculation.

- We will develop, execute, and verify update queries to replace data elements that are 

necessary for the calculation of CBI with the word “CBI”. 

- The numerical values that could be deduced are:

 “Number of Days in Operation” for a Steam Electric Generating Unit, could be 

deduced from the following data fields:

 “Total Duration of Planned/Scheduled Routine Maintenance Outages 

(hours/year)”
November 14, 2012 Abt Associates | Economic and Financial Data Sanitation Plan | pg 3

 “Total Duration of Outages Planned/Scheduled to Address Major Upgrades 

(hours/year)”

 “Duration of Forced/Unscheduled Outages for this Unit (hours/year)”

 “Fuel Costs ($)” for a Steam Electric Generating Unit, could be deduced from the 

following data fields:

 “Quantity of Fuel Burned (Units)”

 “Average Cost of Fuel Per Unit of Fuel Burned ($/unit)”