The Consumer Expenditure Survey: Quality Control by Comparative Analysis
Gieseman, Raymond, Monthly Labor Review
The Consumer Expenditure Survey: quality control by comparative analysis Postsurvey evaluation in an integral part of a program of quality assurance for the ongoing Consumer Expenditure Survey (CE). Comparisons with data from independent sources serve to monitor consistency of results from the survey and help identify areas where survey performance can be improved. This article highlights some of the findings obtained by comparing aggregate consumer expenditures from the CE with data from alternative sources.
The expenditure survey described
The Consumer Expenditure Survey provides a continuous and comprehensive flow of data on the expenditures, income, and other selected characteristics of American consumers. The survey, which is conducted by the Bureau of the Census for the Bureau of Labor Statistics, consists of two components: (1) A Diary, or recordkeeping, survey completed by participating consumer units for two consecutive 1-week periods; and (2) an Interview survey in which the expenditures of consumer units are obtained in five consecutive quarterly interviews.
Each component of the survey addresses an independent sample of consumer units which is representative of the U.S. population. Over 52 weeks of the year, 5,000 consumer units are sampled for the Diary survey. Because each unit keeps a diary for two 1-week periods, approximately 10,000 diaries are obtained each year. The interview sample is selected on a rotating panel basis, targeted at 5,000 consumer units each quarter. The data are collected on an ongoing basis in 101 areas of the country.
The Interview survey is designed to capture expenditures which respondents can recall for a period of 3 months or longer. In general, these include relatively large expenditures, such as those for real property, automobiles, and major appliaces, or expenditures which occur on a fairly regular basis, such as rent, utility payments, or insurance premiums. The Interview survey also provides data on expenditures incurred while on overnight trips and vacations. Including "global estimates" of spending for food, About 95 percent of all expenditures are covered in the Interview phase. Excluded are nonprescription drugs, household supplies, and personal care items.
The Diary survey is designed to obtain detailed expenditures on small, frequently purchased items which are normally difficult for respondents to recall. Records of expenses are kept for food and beverages, both at home and in eating places, tobacco, housekeeping supplies, nonprescription drugs, and personal care products and services. This kind of detail is needed for the periodic rebasing of the Consumer Price Index. Expenditures incurred by members of the consumer unit while away from home overnight or longer are not collected in the Diary survey. CE estimates of food expenditures are particularly affected by this feature.
Expenditure estimates from the CE are transaction costs, including excise and sales taxes, for goods and services acquired during the survey reference period. The full cost of each purchase is recorded, even though full payment may not have been made at the time of purchase. Business-related expenditures and reimbursed expenses are excluded.
Even from this limited description, one can discern a number of possible sources of error in the expenditure survey. As in all sample surveys, the results are subject not only to sampling error, but also to many of the same limitations that would apply to a complete census. The time and effort required to keep a diary of purchases, or to complete an interview, are quite likely to have an impact on the completeness with which expenditures are reported by respondents. Aspects of the collection methodology, interviewer quality, environmental conditioning, processing error, and other factors influence the findings.
There can be overreporting or underreporting of the expenditures. …