2001 Survey MethodsOverviewThe Residential Energy Consumption Survey (RECS)
Detailed
tables based on results of the Household Survey are now available
on the web. The data collection contractor collected and processed the 2001 RECS data for EIA. The data was collected using the Household Survey Questionnaire (PDF format). | ||||||||
| Sample Design | Data Collection Procedures |
| RECS Household Survey | Data Editing |
| Conducting the Interviews | |
| Confidentiality of Information | |
The sample design for the 2001 RECS was based on the design used for the 1993 RECS, which was a multistage area probability design.
In a multistage area probability sample design, the universe is broken up into successively smaller, statistically selected areas. The process starts with the selection of primary sampling units (PSUs) and ends with the selection of individual households.
Primary
Sampling Units (PSUs)
PSUs are either metropolitan areas containing a central city of 50,000 or larger population, or they are counties or groups of counties containing small cities and rural areas. In the sample design used for the 2001 RECS, the total land area of the 50 States and the District of Columbia was divided into 1,786 PSUs. These PSUs were based on county and independent city boundaries and on Metropolitan Statistical Areas (MSAs) as defined in June 1990. The primary mode of stratification of PSUs was by the nine Census divisions. Strata were separately defined within Census divisions for four populous States (California, Florida, New York, and Texas) and for two States with unique weather conditions (Alaska and Hawaii). Stratification was also based on MSA or nonMSA status of PSUs and, to the extent feasible, on dominant residential space-heating fuel and weather conditions. PSUs were grouped into 116 strata with one PSU selected from each strata. The PSUs that were selected for the 1993 RECS were also used for the 2001 RECS.
Secondary Sampling Units (SSUs)
A number of SSUs, usually eight or more, were selected in each PSU. SSUs consisted of one or more Census blocks, selected directly from Census statistics. Blocks were combined, as necessary, to create SSUs that contained at least 50 housing units. SSUs that contained very large numbers of housing units were divided into smaller listing segments and one listing segment was selected for detailed address listing.
New Construction Canvass
The starting point for the SSU new construction update procedure was the set of SSUs selected for the 1997 RECS. The first step was to expand the 1997 SSUs to include selected blocks in the same PSU, creating groups of blocks with at least 400 housing units. A new construction update procedure was used to determine if significant new construction--defined as groups of 50 or more housing units--had occurred within the expanded SSUs since 1997. This was based on a canvass, primarily by telephone, of local sources of information, such as building-permit-issuing agencies, zoning boards, and tax offices. If no significant new construction had occurred, the SSU selected for the 1997 RECS was used for the 2001 RECS. If significant new construction had occurred, rough counts of the number of housing units by block were obtained for the expanded SSU, the expanded SSU was divided into segments, and a segment was selected. The selected segment was then used as the SSU for the 2001 RECS.
The detailed field listings of all housing units in the 2001 RECS SSUs were either carried over from the 1997 RECS or were created by field workers who visited the SSUs and identified each housing unit by street address, apartment number, or other obvious features.
Addresses of these housing units were placed in a database used for actual sample selection.
Sample Selection--Ultimate Clusters
Specific addresses chosen from each of the field listings comprised the ultimate clusters of the 2001 RECS sample. An ultimate cluster of housing units to be contacted for interview (averaging over four 4 housing units for the 2001 RECS) was randomly selected by computer from the penultimate cluster; these housing units constituted the assignments given to interviewers.
Population of Special Interest
The 2001 survey featured a supplemental sample of LIHEAP recipients designed to be merged with the main RECS sample and to meet special analytical needs of the Office of Family Assistance, Family Support Administration (FSA), U.S. Department of Health and Human Services. The FSA is interested in households living below the poverty level. The initial RECS housing characteristics report will use only the households selected as part of the area probability sample.
A complete RECS interview consists of data for a completed household questionnaire and a signed Authorization Form. The large majority of interviews were completed via a Computer Assisted Personal Interviewing (CAPI) system. EIA personnel programmed the survey instrument in the BLAISE software system. The paper version of the survey instrument can be found in Form EIA-457A, "Household Questionnaire." When technical problems were encountered, interviews were completed using the paper version of the questionnaire. At the end of each interview, the household respondent was asked to sign an Authorization Form. The signed Authorization Form gave permission for EIA to obtain the housing unit's energy bills from each fuel supplier provided by the respondent during the course of the interview. The case management system employed was SurveyTrak, which was developed by the University of Michigan.
To accommodate interviewers from various parts of the country, two main training sessions were held-each of which were 4 1/2 days long. The first session was held March 21 through March 25, 2001, in Atlanta, Georgia; and the second session, March 28 through April 1, 2001, in Grapevine, Texas. Only interviewers with little or no CAPI experience attended the first day of each of these sessions. To augment the staff lost to attrition and to provide extra coverage for low-response-rate areas, a third training session was held June 7 through June 10, 2001. Because all the interviewers attending this training were experienced with CAPI administration, this session was 3 1/2 days in length. Approximately 190 interviewers were in attendance across all sessions (80 at each of the main trainings and 30 at the supplemental training). Each session was led by a group of trainers who had attended a 3 day workshop in Princeton, New Jersey. Department of Energy staff, who also participated in the training, monitored all training sessions.
The Interviewers
A total of 158 interviewers completed one or more personal interviews for this study. Sixty-one interviewers (39 percent) had completed interviews during a prior RECS. The remainder were conducting their first RECS, but had prior interviewing experience, either with other survey research organizations or with the US Bureau of the Census.
Interviewers conducted an average of 29 interviews. Forty interviewers completed fewer than ten interviews each, with an average of five per interviewer. Twenty-five interviewers completed 50 or more interviews each, with an average of 72 per interviewer. Thirty-two percent of the personal interviews were verified by telephone or mail to ensure that interviews were conducted as intended.
The InterviewHousehold interviews were conducted with the householder or the householder's partner. The questions covered energy-related features of the household, such as the type of heating and cooling systems; the fuels used for heating and cooling; household appliances and their usage; the receipt of government assistance for the cost of heating and cooling; and demographic data on household members. Interviewers also asked permission to measure the household's living quarters.
Multiwave, Multicontact Approach
In an effort to minimize nonresponse and, therefore, maximize the validity of the survey data, a multiwave, multicontact approach was employed. Before the initial personal contacts, a letter stressing the purpose and importance of the survey was sent to each household with a street address. Beginning in late March 2001, interviewers made several callbacks at different times of the day and different days of the week in an effort to minimize the number of uncontacted households. The interviewers also queried neighbors regarding the most opportune times to contact the prospective respondent.
After initial attempts to complete interviews at the selected housing units were exhausted, field supervisors determined which cases would be reassigned to another interviewer. Types of non-interviewed households that were reassigned included cases where the householder refused to participate and cases where the householder was not available or not at home. Types of non-interview households that were not reassigned included cases where the householder would be unable to complete an interview during the field period due to absence or illness and cases where the household had moved after the initial contact. Reassignments continued throughout the field period.
Data Collection Period
The data collection field period lasted 6 months. Approximately three-quarters of the personal interviews were completed between the end of March through the first week of July 2001 (15 weeks). Ninety-nine percent of the personal interviews were completed by September 29, 2001. In a few sample locations with low response rates, interviewing continued through October 7, 2001.
Mail Questionnaire
In late August, mail follow-up attempts were made at households that had not completed a personal interview. An abbreviated, self-administered version of the questionnaire was mailed to 1,991 of these households with a letter asking that they return the completed questionnaire in the business reply envelope provided. The mailing also included a copy of the Authorization Form for the respondents to sign. A mail questionnaire was considered usable if the respondent had completed the majority of the questionnaire and the Authorization Form was signed. A total of 241 usable mail questionnaires were returned by the end of October 2001.
Households to which a mail questionnaire was sent were given the option of completing the questionnaire via the Internet. Seven sample households responded via this mode.
Authorization Form Follow-up
A follow-up contact was attempted with all respondents who completed a personal or mail interview and reported paying for at least one fuel but did not sign an Authorization Form. Sixty-four additional forms were obtained through this effort.
Overall Response Rate
After all data collection attempts (both personal interview and the mail questionnaire) 4,822 households completed a personal interview, 241 households completed a mail questionnaire, and seven households responded via the Internet.
Response
Rates and Household Characteristics
Various response and non-response rates will be compared across Census region, urban status, and housing structure type later in the analysis stage.
Data for completed interviews were transmitted to the data collection contractor's headquarters via modem using SurveyTrak sample management system. All completed interviews were combined into one Blaise database for further processing. All paperwork, which included the Authorization Form, Measurement Booklet, and Housing Unit Address Lists were mailed to the data collection contractor's headquarters. Contact information from the Blaise interview, the Housing Unit Record from the SurveyTrak sample management system, and the Authorization Form were reviewed to ensure that each had been completed correctly and that the correct housing unit had been interviewed.
Checks and edits were programmed into the Blaise data capture instrument for the Household Questionnaire to reduce the amount of missing or invalid responses. In addition, to ensure the overall quality of the data, checks were programmed in SAS and used to identify range, logic, and consistency problems.
The data collection collection contractor attempted to resolve inconsistencies or ambiguities in the data by referencing interviewer notes and other parts of the questionnaire. When these efforts failed to resolve important problems, particularly those involving heating fuels or heating equipment and/or relationships between questionnaire responses, a follow-up telephone contact with the rental agent or with a member of the household in question were made.
Rental
Agent Survey
In addition, 401 follow-up contacts were conducted with rental agents for households who did not pay for their fuels, who rent their living quarters or own and occupy living quarters in a condominium or cooperative building or community were attempted with rental agents, landlords, and apartment managers. Respondents to this survey were asked about the heating, water heating, and cooking fuels used by tenant households; the household's heating equipment; and method of bill payment (i.e., included in rent or paid by household).
The interviews with rental agents or their representatives were conducted in November 2001. Altogether, 57 landlords or rental agents were interviewed; these interviews covered 127 households. Comparisons were made between rental agents' and household respondents' reports on their main space-heating and water-heating fuels; main space-heating equipment; fuel for cooking range; and how the fuels for all of these uses are paid. Each discrepancy was examined, and changes were made to the household data whenever it was judged that the rental agent was more knowledgeable than the household respondent on the different items of information.
Generally, the person who paid for a specific fuel for a specific use was deemed the most knowledgeable person. However, error resolutions were made only after careful examination and consideration of all available sources of information including the rental-agent questionnaire, the household questionnaire, and questionnaires of other households located in the same building. Landlords and rental agents were usually judged to be more knowledgeable about the type of main heating equipment; household respondents were typically deemed more reliable sources concerning fuel for cooking range.
LIHEAP (Low-Income Home Energy Assistance Program)
Of the 840 households selected to participate in the LIHEAP Supplement, completed interviews were obtained for 497 households. This section describes the sample plan and the procedures involved in collecting the completed interviews.
Sample Plan
Interviewer Training
A subset of the 2001 RECS interviewing staff was trained via conference call on the specific requirements of the LIHEAP Supplement. Such training was necessary because of the differences in the sample management aspects of the study between the main survey and the supplemental sample. The field supervisory staff to whom the interviewers were assigned for the 2001 RECS conducted the training session.
The Interviewers
A total of 36 interviewers completed 1 or more personal interviews for the LIHEAP Supplement. Interviewers conducted an average of 12 interviews. Four interviewers completed fewer than five interviews each, with an average of three per interviewer. Six interviewers completed 20 or more interviews each, with an average of 24 per interviewer. A percentage of all interviewers working on the supplemental sample had passed verification procedures during the main RECS survey. However, verifications did continue for supplemental of interviews at reduced levels by mail.The Interview
Unlike the main sample where the interview was conducted with the current occupant of an eligible housing unit, interviewers were directed to interview a member (householder or partner or spouse of the householder) at a designated housing unit. If the family no longer lived at that address, the interview was not conducted. Lists of LIHEAP households were obtained from individual State LIHEAP offices.
Other than the differences in sample management and the identification of the respondent to be interviewed, the same materials and protocol as those used in the main study were employed.
Data Collection DatesThe data collection field period for the LIHEAP supplement began July 20, 2001, and was completed in December. Each PSU was given a minimum of 4 weeks for completion. There was no mail questionnaire follow-up for sample households in the LIHEAP Supplement who did not complete a personal interview.
Data Collection Procedures
Before the initial personal contacts, a letter stressing the purpose and importance of the survey was sent to each household with a street address. For households with only Post Office box addresses, letters were mailed to those addresses asking the sample members to call to arrange an interview.
Beginning in mid-July 2001, interviewers made several callbacks at different times of the day and different days of the week in an effort to minimize the number of uncontacted households. The interviewers also queried neighbors regarding the most opportune times to contact the prospective respondent. For the most part, a single interviewer was responsible for a PSU. If that interviewer was unable to achieve the targeted goal for the PSU, an interviewer traveled from another PSU to complete the assignment.
Response Rates and Household Characteristics
Various response and non-response rates will be compared later in the analysis stage.
Data Editing
Data for completed interviews in the LIHEAP Supplement will be were subjected to the same data editing steps as those cases in the main sample.
Confidentiality of Information
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