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| CBECS Home Page 1. How the Survey Was Conducted:
Return to: 1995 Detailed Tables |
During the Building Characteristics Survey, each respondent was asked to provide the name, address, and account numbers for all suppliers of energy to the building. In addition, respondents were asked to sign an authorization form that gave permission to the suppliers to release the building’s monthly billing data to EIA. EIA’s survey contractor sent copies of this form to the suppliers to secure the release of the buildings’ billing records, as well as the buildings’ participation in any demand-side management programs, if programs were available from the energy supplier. Attempts were made to contact all suppliers of electricity, natural gas (including suppliers of natural gas transported for the account of others), fuel oil, district sources (steam, hot water, and chilled water) that were identified during the Building Characteristics Survey. Data Collection Instruments Consumption and Expenditures Forms: Each supplier of electricity, natural gas, fuel oil, or district sources to a sampled building was asked to provide consumption and expenditures data on a mailed survey form. Because there were minor differences in data items by energy source, there were corresponding variations in the reporting forms as well. For example, the electricity forms requested kilowatt (kW) demand; the natural gas forms included transportation gas, as well as provision for reporting variable units of measures (such as therms, cubic feet, or 1,000 cubic feet); the fuel oil forms requested information about the type of fuel oil used; and the district heating forms asked for information concerning the entire district or system. Despite the above-mentioned differences, the forms for the different fuels were similar in terms of the data requested. In each case, the supplier was asked to report the following data: (1) quantity of specific energy source consumed or delivered; (2) total cost; (3) unit of measure; (4) dates of deliveries or consumption; and (5) number of customers included in both the consumption and cost data reported on the form. Suppliers were not required to transcribe data onto the survey forms—responses were accepted in any format (including computer printouts), as long as the necessary information was provided. Additionally, electric, natural gas, and fuel oil suppliers could submit their data on a formatted computer diskette provided by EIA. Response to the forms was mandatory for the supplier. The data were requested for a 14-month period between December 1, 1994, and January 31, 1996, in order to ensure that data would cover a full calendar year no matter what the actual billing period had been. For example, if the billing period began on the 10th of each month, the first bill would be from December 10 through January 9. The bills were then prorated (annualized) to obtain data for the calendar year. Demand-Side Management (DSM) Forms: An additional form was inserted in the electricity and natural gas usage forms to collect data about the building’s participation in utility-offered energy-savings programs. Both forms collected essentially the same type of information, although each was tailored to the particular energy source, either electricity or natural gas. For example, the electricity suppliers were asked about DSM programs, such as lighting, energy-efficient motors, metered peak demand, time-of-day pricing, and standby electricity generation. The natural gas form asked about DSM programs but did not include those measures that were not applicable to natural gas suppliers, such as peak demand or time-of-day pricing. Data Collection Advance Mailings: An initial letter from EIA was mailed in September 1995 to electricity and natural gas utility companies that served buildings surveyed in the 1992 CBECS, explaining the survey and requesting a contact person be designated for the 1995 survey. A second letter from EIA, which included a copy of the 1992 CBECS executive summary from the Commercial Buildings Energy Consumption and Expenditures 1992, was mailed in November 1995 to companies that had not responded to the earlier request for information. Survey Mailings: For the 5,766 buildings for which responses had been obtained in the Building Characteristics Survey, a total of 11,091 energy suppliers forms were mailed to 1,218 suppliers of energy. Of these suppliers, 518 (43 percent) were electricity and natural gas suppliers (including suppliers of gas transported for the account of others), 415 (34 percent) were fuel oil suppliers, and the remaining 285 (23 percent) were district heating suppliers. The initial mailing of the survey forms to the energy suppliers occurred in early February 1996, with a due date of March 1, 1996, for the forms. Reminder letters to suppliers who had not returned the forms were sent shortly after the due date, with a second written request to nonrespondents in May 1996. Survey closeout was September 5, 1996 (the closeout date was extended by 3 weeks to accommodate several late-responding suppliers.) Minimizing Nonresponse Extensive efforts were used to obtain usable energy supplier data. Letters and telephone prompts were made to the energy suppliers throughout the data collection period to remind the suppliers to provide the data within the required time period. In addition, a toll-free telephone hot-line number was provided to all suppliers, both in the cover letter accompanying the survey forms and on the face of each survey form. Suppliers were encouraged to call this number if they had any questions. Hot-line staff were knowledgeable regarding the most frequent technical problems encountered by suppliers and the instructions to be given to suppliers calling with these questions. Electricity, Natural Gas, and Purchased District Heat Suppliers: The nonresponse effort for the suppliers of electricity, natural gas, and purchased district heat began with a personalized reminder letter to all companies that had not returned any survey forms as of the March 1, 1996, date. Another nonresponse conversion letter was mailed May 1, 1996, to companies that had returned some but not all of their forms, as well as to companies that had not responded at all. Beginning May 23, 1996, nonrespondents were then telephoned and asked for the expected forms’ completion date. These calls resulted in 128 requests for more forms. The companies were called again if that date arrived and they still had not responded. The nonresponse procedure was followed both for complete nonresponse by an energy supplier and for incomplete or missing buildings within a supplier’s response. Fuel Oil and Nonpurchased District Heat Suppliers: On March 6, 1996, a reminder letter was sent to each fuel oil supplier and each supplier of nonpurchased district heat that had not returned all forms. This was followed in April by a remailing of the entire packages of survey forms to those companies that had not yet responded. Telephone nonresponse conversion calls began on June 5, 1996, after a third letter was sent in May alerting the respondent to the telephone calls. The telephone calls resulted in numerous requests for additional survey forms, which were mailed in mid-June to 57 companies. When possible, the telephone interviewers attempted to obtain data over the telephone if a limited number of survey forms was missing. Energy Suppliers Survey Response Rates: The overall response rate for the 1995 Energy Suppliers Survey was 84.9 percent (see Table 1 at end of section). The response rate is defined as: Each record corresponded to a single energy supplier for a particular energy source to a particular building. For example, a building with one electricity supplier, two fuel oil suppliers, and no other energy suppliers would have a total of three energy supplier records, one for electricity and two for fuel oil. Records were initially created on the basis of the Building Characteristics Survey respondents’ reports of the names and addresses of their energy suppliers. A record was declared out-of-scope if it turned corresponded to a supplier that did not actually serve the building during calendar year 1995. Response rates for natural gas (not identified as gas transported for the account of others) and for electricity were 86.5 and 89.1 percent, respectively, which were similar to results obtained in previous CBECS. The response rate for the suppliers of gas transported for the account of others was 79.1 percent. The response rate for fuel oil was 77.7 percent and the rates for steam and hot water (district sources) were 62.3 percent and 25.7 percent, respectively. Of the forms mailed, 1,516 (about 14 percent) were classified as nonresponse. That category included refusals, inability to respond within the data collection period, and inability to locate the correct account for the building. Data Editing As the suppliers’ forms were received, they were screened for accuracy and completeness. The forms were then keyed and edited. (In 1995, for the first time, PC-based key entry was used for the suppliers survey forms.) The Energy Suppliers Survey used an extensive program of automated machine edits, including: (1) Basic Energy Range and Skip Checks. EIA specified ranges and values to be used for the technical edits. These values were based on previous CBECS responses and on knowledge of utility rates and practices. The first edits were range and basic logic checks.Data Adjustments: Adjustments for unit nonresponse were performed in conjunction with weighting of the sample. Cases missing all or part of calendar year 1995 consumption or expenditures were considered as a particular kind of item nonresponse. Weather Data: A file of heating and cooling degree-days for each of the billing periods reported by each building supplier was created in the following manner: A National Oceanic and Atmospheric Administration (NOAA) division code was assigned to each building in the CBECS sample. Working with NOAA division maps and building address information, EIA assigned one of 356 division codes to each building.Data Preparation for Report After receiving the CBECS data tapes from the survey contractor, EIA data analysts reviewed and processed the data to prepare them for the final data tape. Cross-tabulations were run to check for internal consistency of the data, and the 1995 CBECS data were compared with data from previous CBECS. Commercial buildings’ consumption and expenditure data are complex and interrelated. The EIA review was extensive and paid special attention to the issues of peak electricity demand, gas transported for the account of others, and incomplete data for buildings. Questions concerning data accuracy or outlier values were referred to the survey contractor for verification. EIA staff reviewed the data questionnaires at the survey contractor’s site, and EIA’s staff judgment was the final authority on some of the data items. The sections above on data editing, data adjustments, and weather data provide details on the work undertaken to prepare the data for this report. In addition, if retrieval of missing data for one or more items failed, or if retrieval was not performed because the item was not a key item, data values were supplied by imputation. Additionally, the consumption and expenditures data were annualized; that is, they were adjusted by proration methods to estimates for calendar year 1995, when the reported data spanned a longer, shorter, or offset time period. When consumption or expenditures data were completely missing, the annual amounts were imputed by regression. Once the annualized consumption and expenditures were computed or imputed for each building, statistical tables (“Detailed Tables”) of aggregated data were then produced and analyzed. Top Return to “1995 Detailed Tables” |
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Table 1. Response Rates for Energy Suppliers Survey by Energy Source, 1995 |
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