Editor's note: The following article is an excerpt from a U.S. Dept. of Commerce report, "Approaches to Developing Questionnaires."

The National Health Interview Survey (NHIS) is a repetitive survey which collects health and demographic information from a national sample of about 40,000 households each year. Field operations for the survey are performed by the Bureau of the Census under specifications established by the National Center for Health Statistics (NCHS).

With the objective of fielding a revised NHIS questionnaire in the early 1980's, a series of field tests was planned to test an evaluation version of the NHIS questionnaire. The evaluation version, or experimental questionnaire, was designed to eliminate redundancies, define health concepts more explicitly, present topics in a more logical order and enable interviewers to use the material efficiently and smoothly. In conjunction with the results of a statistical analysis of the test data, the feedback from an extensive program of observation provided the basis by which to judge whether the objectives of the redesign had been achieved.

The testing was conducted in three phases.

1. Phase I (June). The first version of the evaluation questionnaire was administered in 250 households in Springfield, Ohio, by 15 Bureau of Census interviewers. The primary purpose of this informal test was to form a qualitative or subjective assessment of the draft instrument.

2. Phase II (October-December). This phase of the testing was designed as a formal (split sample) test to quantitatively assess the revised evaluation questionnaire by comparing selected estimates produced by the standard NHIS document and the experimental document. The control group, consisting of the fourth-quarter NHIS sample (10,500 households), received the standard questionnaire. The experimental group receiving the evaluation questionnaire contained 5,000 househo...