Consumer Expenditures and Income: Sample Design
Design selection of households
The Consumer Expenditure Survey (CE) is a nationwide household survey representing the entire U.S. civilian noninstitutional population. It includes people living in houses, condominiums, apartments, and group quarters such as college dormitories. It excludes military personnel living overseas or on base, nursing home residents, and people in prisons. The civilian noninstitutional population represents more than 98 percent of the total U.S. population.
The selection of households for the survey begins with the definition and selection of primary sampling units (PSUs). PSUs are small clusters of counties grouped together into geographic entities called “core-based statistical areas” (CBSAs), which are defined by the Office of Management and Budget (OMB) for use by federal statistical agencies in collecting, tabulating, and publishing federal statistics. The CE currently uses OMB definitions from 2012. There are two types of CBSAs: metropolitan and micropolitan. Metropolitan CBSAs are areas that have an urban “core” of 50,000 or more people, plus the adjacent counties that have a high degree of social and economic integration with the core as measured by commuting ties. Micropolitan CBSAs are similar to metropolitan CBSAs but they have an urban core of 10,000 to 50,000 people. Areas without an urban core or whose urban core is under 10,000 people are called non-CBSA areas. See https://www.census.gov/population/metro/.
Starting in 2015, the geographic sample used in the survey consists of 91 PSUs based on population numbers from the 2010 Decennial Census that are classified into three categories:
- 23 “S” PSUs, which are metropolitan CBSAs with a population over 2.5 million people (self-representing PSUs)
- 52 “N” PSUs, which are metropolitan and micropolitan CBSAs with a population under 2.5 million people (nonself-representing PSUs)
- 16 “R” PSUs, which are non-CBSA areas (“rural” PSUs)
The 23 “S” PSUs are the largest CBSAs in the country, and they were selected with certainty for the CE sample. The 52 “N” and 16 “R” PSUs are smaller CBSAs that were randomly selected from the rest of the country, with their probabilities being proportional to their populations. The 23 “S” and 52 “N” PSUs are also used by the Consumer Price Index program, but not the 16 “R” PSUs because the CPI measures inflation only in urban areas of the country.
Within these 91 PSUs, the list of addresses from which the sample is drawn comes from two sources called “sampling frames.” The primary sampling frame for both the Diary Survey and the Interview Survey is the Census Bureau’s Master Address File (MAF). That file has all residential addresses identified in the 2010 census and is updated twice per year with the U.S. Postal Service’s Delivery Sequence File. Over 99 percent of the addresses used in the survey come from the MAF. It is supplemented by a small Group Quarters frame, which is a list of housing units that are owned or managed by organizations for residents who live in group arrangements such as college dormitories and retirement communities. Less than 1 percent of the addresses used in the CE come from the Group Quarters frame.
The Census Bureau selects a sample of approximately 12,000 addresses per year from these two frames to participate in the Diary Survey. Usable diaries (two 1-week diaries per household) are obtained from approximately 6,900 households at those addresses. Diaries are not obtained from the other addresses due to refusals, vacancies, ineligibility, or the nonexistence of a housing unit at the selected address. The placement of diaries is spread equally over all 52 weeks of the year.
The Interview Survey is a rotating panel survey in which approximately 12,000 addresses are contacted each calendar quarter of the year for the survey. One-fourth of the addresses that are contacted each quarter are new to the survey. Usable interviews are obtained from approximately 6,900 households at those addresses each quarter of the year. After a housing unit has been in the sample for four consecutive quarters, it is dropped from the survey, and a new address is selected to replace it. Before 2015, the Interview Survey included a preliminary bounding interview, and each CU could be contacted up to five times over five quarters. The bounding interview, which recorded recent major expenditures for comparison with subsequent purchases, was determined to be unnecessary, and was dropped at the beginning of 2015 to save money and reduce respondent burden and collection costs. See https://www.bls.gov/cex/research_papers/pdf/Recommendation-Regarding-the-Use-of-a-CE-Bounding-Interview.pdf.
Response data for the 2013 CE are shown in table 1. For the Interview Survey, each unique housing unit provides up to four usable interviews per year. For the Diary Survey, each unique housing unit provides up to two usable diaries (weeks 1 and 2). Most Diary Survey respondents participate in both weeks.
There are three general categories of nonresponse:
- Type A nonresponses are refusals, temporary absences, and noncontacts.
- Type B nonresponses are vacant housing units, housing units with temporary residents, and housing units under construction.
- Type C nonresponses are nonresidential addresses, such as destroyed or abandoned housing units, and housing units converted to nonresidential use.
Response rates are defined as the percentage of eligible housing units (that is, the designated sample less Type B and Type C nonresponses) from which usable interviews are collected by the Census Bureau. In the 2013 Interview Survey, there were 48,920 eligible housing units from which 32,822 usable interviews were collected, resulting in a response rate of 67.1 percent. In the 2013 Diary Survey, there were 19,252 eligible housing units from which 12,511 usable interviews were collected, resulting in a response rate of 65.0 percent. (See table 1.)
|Sample unit||Interview Survey||Diary Survey|
Housing units designated for survey
Less: Type B and type C nonresponses
Equals: Eligible units
Less: Type A nonresponses
Equals: Interviewed units
Percentage of eligible units interviewed
1In 2015, the number of interviews per household decreased from five to four. The data in this table are from 2013, so the numbers in the Interview Survey column are approximately 25 percent larger than they will be starting in 2015.
2The number of Diary Survey addresses (12,740) multiplied by two weekly diaries.
Note: Type A nonresponses are refusals, temporary absences, and noncontacts. Type B nonresponses are vacant housing units, housing units with temporary residents, and housing units under construction. Type C nonresponses are nonresidential addresses, such as destroyed or abandoned housing units, and housing units converted to nonresidential use.
Source: U.S. Bureau of Labor Statistics.
Last Modified Date: February 25, 2016