The Commercial Buildings Energy Consumption Survey (CBECS) is conducted quadrennially by the Energy Information Administration (EIA) to provide basic statistical information about energy consumption and expenditures in U.S. commercial buildings and information about energy-related characteristics of these buildings. The survey is based upon a sample of commercial buildings selected according to the sample design requirements described below. A “building,” as opposed to an “establishment,” is the basic unit of analysis for the CBECS because the building is the energy-consuming unit.  The 2003 CBECS was the eighth survey conducted since 1979

The CBECS is conducted in two data-collection stages: a Building Characteristics Survey and an Energy Suppliers Survey.  The Energy Suppliers Survey is initiated only if the respondents to the Building Characteristics Survey can not provide the energy consumption and expenditures information, or the information provided fails edits within the survey instrument. The Building Characteristics Survey collects information about selected commercial buildings through voluntary interviews with the buildings’ owners, managers, or tenants.  In the 2003 survey, these data were collected using Computer-Assisted Personal Interviewing (CAPI) techniques.

During the Building Characteristics Survey, respondents are asked questions about the building size, how the building is used, types of energy-using equipment and conservation measures that are present in the building, the types of energy sources used, and the amount and cost of energy used in the building.

Upon completion of the Building Characteristics Survey, the Energy Suppliers Survey is initiated for those cases that did not provide satisfactory consumption and expenditures information. This Suppliers Survey obtains data about the building’s actual consumption of and expenditures for energy from records maintained by energy suppliers.  These billing data are collected in a mail survey conducted under EIA’s mandatory data collection authority. A survey research firm, under contract to EIA, conducts both the interviews for the Building Characteristics Survey and the mail survey for the Energy Suppliers Survey.

2003 CBECS

This document describes the 2003 CBECS sample design, including the target population, the sample frames and sample selection rates, response rates, and the adjustment for unit nonresponse.  Other information about survey procedures and methodology can be found in "Technical Information on CBECS" and "Background Information on CBECS".

Target Population

The target population for the 2003 CBECS consisted of all commercial buildings in the United States (with the exception of commercial buildings located on manufacturing sites) that were were larger than 1,000 square feet.

To be eligible for the survey, a building had to satisfy three criteria: (1) it had to meet the size criteria described above; (2) it had to meet the survey’s definition of a building; and (3) it had to be used primarily for some commercial purpose.  To be considered a building for CBECS, a structure must be totally enclosed by walls that extend from the foundation to the roof and must be intended for human access. To be used primarily for some commercial purpose, the building must have more than 50 percent of its floorspace devoted to activities that are neither residential, industrial, nor agricultural. The 2003 CBECS estimated that there were 4,859 thousand buildings in the target population.

2003 CBECS Sample

The sample of commercial buildings for the 2003 CBECS was selected by a multistage area probability sample supplemented by a sample of buildings drawn from various special list frames within the primary sampling units (PSUs). A new sample of PSUs, which were counties or group of counties, was selected. For the area sample, a sample of secondary sampling units (SSUs), composed of U.S. Census Bureau tracts, was selected within the PSUs. Some of the large SSUs were divided into segments, which were composed of Census Bureau block-groups. In these large SSUs, one segment was selected from each SSU. Lists of all commercial buildings in each of the sampled segments were prepared by field listing. Building size and use classes, based on observation, were assigned by the listers to each listed building. The buildings were selected from these field lists by overall sampling rates that varied by the size and use class of the building.

The basic area probability sample design was supplemented by list samples of large buildings in each PSU to improve the precision of energy consumption estimates. The list supplementation was designed to give the larger buildings (those with 200,000 square feet or more) more nearly optimum probabilities of selection for estimating aggregate statistics correlated with square footage. The list samples were selected within the sample PSUs from special lists of Federal Government buildings, colleges, universities, hospitals, large office buildings, and other types of commercial buildings. The buildings from these lists were also selected by overall sampling rates that varied by the size and use class of the building. Special subsampling procedures were used to reduce respondent burden on campuses and in shopping centers.

Shopping Mall Procedures

A major change for the 2003 CBECS was the implementation of subsampling establishments within strip shopping centers of enlcosed malls, and subsequently conducting separate interviews in these establishments. In the past, an attempt was made to administer an interview for each mall as a whole. The new procedure was implemented to improve the quality of data for shopping centers and malls because interviewers learned from previous CBECS cycles that it is difficult to find a respondent who has overall knowledge about these buildings as a whole.

At their first visit to each sampled shopping center or mall, interviewers listed each establishment along with a very general category of the type of business; the list was faxed to the survey contractor, where up to three establishments were subsampled; a list of selected establishments was returned to the interviewer, and interviews were attempted. This establishment data will be aggregated to the shopping center or mall level for published reports. Shopping center or mall cases were considered to be complete as long as the list of establishments was complete. 

Sample Size

A sample of 6,955 potential building cases was selected (including mall buildings but not the individual establishment cases), consisting of 6,120 buildings from the area sample frame and 835 buildings from the special list frames. Of these 6,955 buildings, 6,380 were found to be eligible for interviewing.

For establishments within malls, a sample of 880 was selected, comprised of 768 establishments from the area sample and 112 from the list sample. All of these were eligible for interviewing.

Response Rates

These procedures resulted in 5,215 completed building interviews for a response rate of 82 percent. This total included 4,683 buildings from the area sample and 532 buildings from the special list samples.

A total of 668 establishment interviews were completed, for a response rate of 76 percent.

Unit Nonresponse

An in-scope sample building, otherwise eligible for interview, for which no information is obtained, is called a unit nonresponse. The principal cause of the 18 percent unit nonresponse among buildings in the 2003 CBECS was the respondent’s refusal to participate in the interview (60 percent).  The second largest reason for nonresponse was the inability to contact and interview someone knowledgeable about the building (31 percent). The remaining 9 percent included a few cases where the respondent did not speak English, buildings that were incorrectly identified during the interview, and miscellaneous other reasons.

Among establishments, 44 percent were refusals and 41 percent were establishments where the correct person was unable to be contacted during the field period. The rate of nonresponse cases where the respondent spoke a language other than English was notably higher for establishments than for buildings (9 percent vs. less than 1 percent).

Adjustments for unit nonresponse were made by redistributing the baseweights of nonresponding buildings to responding buildings with similar propensities for nonresponse. A predictive model for response propensity was developed to identify subgroups of population with differential response rates. The number of variables available for the modeling was not large but included some that should also be highly predictive of energy use such as climate zone, building size and use, and number of floors.

Confidentiality of Information

The names or addresses of individual respondents or any other individually identifiable data that could be specifically linked to an individual sample building or building respondent are seen only by employees of EIA, its survey contractor, and EIA-approved agents.  The data are kept secure and confidential at all times. The 2003 CBECS is the first survey cycle for which EIA took possession of specific building identifiers.  This change, which gives EIA greater capability to handle and manage its data, was the result of a new Federal law, the Confidential Information Protection and Statistical Efficiency Act of 2002 (CIPSEA).  The legislation gives EIA both the authority and the responsibility to protect from disclosure identifiable data which respondents have been promised would be kept confidential and used exclusively for statistical purposes.  The CBECS meets these criteria, and the 2003 cycle was collected under CIPSEA protection.

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