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The 1997 survey featured a supplemental sample of low-income households designed to be merged with the main RECS sample and to meet the special analytical needs of the Office of Family Assistance, Family Support Administration (FSA), U.S. Department of Health and Human Services. FSA is interested in households living below the poverty level that use electricity, fuel oil, or kerosene as the main space-heating fuel.

Procedures for over sampling this population were based on interviewer observations during the listing phase. Interviewers were instructed to rate the general income level of each block in the listing segment based on their observations and their general knowledge of the area. Interviewers placed each listing segment into one of four groups: Wealthy (highest 25 percent); Upper-Middle Class (second quartile); Lower-Middle Class (third quartile); or Poor or Near Poor (lowest 25 percent). Whenever possible, interviewers also recorded main heating fuel for each listing segment. Listing segments used for the below-poverty-level supplement and the relative sampling rates used for specific classes of housing units are shown in Table A1.

Table A1. Relative Sampling Rates Based on Income Rating and Main Home-Heating Fuels

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Source: Energy Information Administration, Office of Energy Markets and End Use, The 1997 Residential Energy Consumption Survey.

A relative sampling rate of 1.0 in Table Al means that the overall sampling rate applied to households in a sample segment is the rate established for the basic sample. Relative sampling rates higher than 1.0 were used for households in the oversampled groups. For example, a relative sampling rate of 1.25 means that households in that group were sample data rate 25 percent higher than the rate established for the basic sample. In addition to the sampling rates shown in Table A1, Households in Alaska were over sampled by an additional 25 percent.

It is not possible to exactly divide the sample into the basic sample and supplemental sample, but it is possible to estimate how many observations of various types were added as a result of the supplemental low-income sample.

The estimated outcome of the oversampling procedure for households below the poverty level is summarized in Table A2. An estimated 807 interviews were completed in the households selected as part of the low-income supplement. Some 31.8 percent of completed interviews in the supplemental sample were with households living below the poverty level, compared with 14.5 percent of completed interviews in the main sample. The corresponding figures for the LowIncome Home Energy Assistant Program (LIHEAP) level were 57.3 percent and 34.1 percent, respectively.

Household Surrvey

A complete RECS interview consists of data for a completed household interview and a signed Authorization Form. The large majority of interviews were completed via a Computer-Assisted Personal Interviewing (CAPI) system. The survey instrument was programmed by using the BLAISE software system.. Form EIA-457A, the paper version of the survey instrument, can be found in Appendix D, "Household Questionnaire." Because of technical problems, some of the interviews had to be conducted via Paper and Pencil Interviewing (PAPI). After the end of each interview, the household respondent was asked to sign an Authorization Form. The signed Authorization Form gave permission for EIA's subcontractor to obtain the housing unit's energy bills from each energy supplier.

A total of 8,310 units were selected to participate in the 1997 RECS. Of these 8,310 households, 7,285 were determined to be eligible to participate. Completed interviews were obtained for 5,900 (81.0 percent) of these eligible households.

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Table A2. Poverty Status and Home-Heating Fuels in the 1997 RECS: Main and Supplemental
Low-Income Samples

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Notes: Households are classified according to the poverty status of the family or nonfamily householder. The actual reference period for income reported in the 1997 RECS was the 12 months preceding the RECS interview; the interview date for most households was within the second and third calendar quarters of 1997. ●Table shows unweighted numbers and percentages of completed units. See Glossary for the definition of poverty.

Source: Energy Information Administration, Office of Energy Markets and End Use, the 1997 Residential Energy Consumption Survey.

Conducting the Interviews

Interviewer Training

In April 1997, two separate three-day training sessions were held in Washington, DC. These sessions were attended by approximately 220 interviewers. Each session was led by a group of trainers who had attended a three-day trainers' workshop in Rockville, MD. The training sessions included: discussion of general interviewing techniques, RECS background, an introduction to the CAPI system and related topics, instruction on sampling issues and the use of the address lists, a series of trainer-guided practice interviews, practice with mock interviews, and a review of administrative requirements. All training sessions were monitored by EIA's staff.

The Interviewers

A total of 214 interviewers completed one or more personal interviews for this study. Seventy-five interviewers (35 percent) had completed interviews on a prior RECS. The remainder were conducting their first RECS but had interviewing experience either with other survey research organizations or with the U.S. Bureau of the Census.

Each interviewer conducted an average of 27 interviews. Four interviewers each completed fewer than seven interviews, with an average of three per interviewer. Fifteen interviewers each completed 50 or more interviews, with an average of 58 per interviewer. Twenty percent of the personal interviews were verified by telephone or mail to ensure that interviews were conducted as intended.

The Interview

Household interviews were conducted with the householder or the householder's spouse and lasted, on average, 29 minutes; nearly 80 percent of the interviews lasted between 15 and 45 minutes. 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 demographic data on household members.

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Approximately three-quarters of the personal interviews were completed between the middle of April and the middle of June. Ninety-nine percent were completed by mid-August. In a few sample locations with low-response rates, interviewing continued through August. The subcontractor conducted a follow-up with all respondents who completed a personal interview and reported paying for at least one fuel but did not complete an authorization form. Attempts were made to secure signed authorization forms from approximately 570 respondents. This follow-up continued through January 1998 and resulted in an additional 95 signed authorization forms. In late August 1997, a shortened version of the questionnaire was mailed to the 1,421 households that had not completed a personal interview. A total of 181 usable questionnaires were returned by the end of September, 1997. A mailed questionnaire was considered usable if the respondent had completed the majority of the questionnaire and signed the Authorization Form.

Data Collection Procedures

In an effort to minimize nonresponse and, therefore, maximize the validity of the survey data, a multiwave, multicontact approach was employed. Before the initial contacts, a letter was sent to each household with a street address. The letter, from the Director of EIA's Office of Energy Markets and End Use, briefly described the purposes and stressed the importance of the survey. Beginning in April 1997, interviewers made several callbacks at different times of the day, throughout 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-interview 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.

Mail follow-up attempts were made at households which had not completed a personal interview. An abbreviated, selfadministered version of the questionnaire was mailed to these households with a letter asking that they return the completed questionnaire in the business reply envelope provided. The questionnaire also included a copy of the Authorization Form for the respondents to fill out and sign. A pen was included with the mailing as an incentive.

The multiwave, multicontact approach was successful in accomplishing the following improvements in response.

A total of 299 household (25 percent) who initially refused later agreed to a personal interview. These cases represented over 5 percent of the personal interviews. An additional 10 percent of the refusals completed a mailed questionnaire.

Twenty-six percent of the interviews were conducted on the first visit to the housing unit. An additional 36 percent of the interviews required only two to three visits. The median number of visits needed to obtain an interview was three.

Of the 181 mailed questionnaires that were completed and returned, 116 (64 percent) were from households that refused to participate in person.

Of special concern during the fieldwork was the prevalence of sample units where access was prohibited primarily because of security measures. Special efforts to contact officials charged with the security were attempted for a total of 13 buildings, comprising 80 households. Of these, interviewers were able to gain access to approximately 7 buildings comprising 40 selected households. Roughly 20 interviews were completed in these buildings. In some cases, interviewers were able to gain access to buildings where the officials had refused to grant entry. These cases would not reflect a final status of "Prohibited Access." In other cases, the subcontractor was able to obtain information from the building officials as to which housing units in a particular building were vacant.

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After all data collection attempts (both personal and the mailed questionnaire) 1,385 households or 19.0 percent of all eligible housing units had not responded. Table A3 provides a summary of the data collection activities.

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5,719

181

5,900

Source: Energy Information Administration, Office of Energy Markets and End Use, Forms EIA-457 A and B of the 1997 Residential Energy Consumption Survey (RECS). RECS Public Use Data Files and unreleased data.

Response Rates and Household Characteristics

Various response and nonresponse rates were compared across Census region, urban status, and housing structure type (Table A4). As noted in this table, personal interviewers were most successful in the South (81.1 percent) and the Midwest (80.2), in rural areas (85 percent), and in single family and mobile homes (80.5 percent). Conversely, the interviewers had their lowest success rates in the Northeast (73.1 percent), in urban and suburban areas (76.4 percent combined), and in buildings with five or more residential units (72.1 percent). When comparing these groups, it is important to remember that their characteristics are not necessarily independent. For example, apartment buildings are concentrated in urban areas.

The total response-rate patterns generally were not affected by including the mailed-questionnaire responses. However, response rates for the mail efforts tended to be higher where the refusal rate to the personal interview was higher.

Data Editing

Data for completed interviews were transferred via modem to the main server at the survey contractor's headquarters. The data were then sent to the survey subcontractor's headquarters for further processing. All paperwork was mailed to the survey subcontractor's headquarters. The paperwork, including the Housing Unit Record Sheet (HURS), the

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Authorization Form, and the Housing Unit Address Lists were reviewed to ensure that all forms had been completed correctly and that the correct housing unit had been interviewed.

Table A4.

Response Rates in the 1997 RECS by Region, Metropolitan Statistical Area Status, and
Type of Structure (Percentage of Eligible Housing Units)

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Source: Energy Information Administration, Office of Energy Markets and End Use, Forms EIA-457, A and B of the 1997 Residential Energy Consumption Survey (RECS). RECS Public Use Data Files and unreleased data.

Edits were programmed into the Household Questionnaire, which resulted in far fewer missing data items than in previous surveys. For more information see Appendix B, "Survey Estimates and Data Quality."

The subcontractor attempted to resolve internal data inconsistencies or ambiguities in the data internally, by referencing interviewer notes and other parts of the questionnaire. When efforts failed to resolve an important problem, particularly those involving heating fuels or heating equipment and/or relationships between questionnaire responses, the subcontractor made a follow-up contact with the rental agent or household respondent.

Rental-Agent Survey

The Rental-Agent Survey is an adjunct to the Household Survey and is used to verify information furnished by certain RECS households on fuels used, main heating equipment, how fuels are paid for, and other energy-related topics. Telephone interviews were conducted by using Form EIA-457C, "Rental Agents, Landlords, and Apartment Managers Telephone Survey," with the rental agents and landlords of the following types of RECS households: households that did not pay for their fuels, and, households who paid a third party for their fuel and who rent their living quarters or own and occupy living quarters in a multi-unit building.

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