Methods of Constructing Health Measures

Published in: Measuring Functioning and Well-Being: The Medical Outcomes Study Approach / edited by Anita L. Stewart and John E. Ware, Jr., (Durham, N.C.: Duke University Press, 1992), Chapter 5, p. 67-85

by Anita Stewart, Ron D. Hays, John E. Ware

In research on health and health-related matters, the concepts are complex and difficult, if not impossible, to define by a single item. Rather, light must be cast at different angles. In constructing measures, the MOS approach was to write questionnaire items; pretest the measures; construct multi-item scales; evaluate scale variability, reliability, and stability; and label measures. This chapter offers criteria for each element of this process. For example, writing questionnaire items required operationalizing the concept being measured; that is, for the MOS, closed-ended questions with a specific set of responses were used, because in large-scale studies, open-ended questions are more burdensome and often yield uninterpretable answers, especially from the less educated. Response options consisted of choices on endorsement (how true/false), frequency, and intensity. A time frame also needed to be specified for most questions. Pretesting was conducted to judge clarity of instructions, determine whether questions made sense, and estimate respondent burden. MOS conducted nine full-scale pilot studies of various measures with varying purposes, spending more than one year on this phase. The chapter includes mathematical formulas for such factors as item-scale correlations uncorrected for overlapping items, scale transformations, reliability, and intra-class correlations.

This report is part of the RAND Corporation External publication series. Many RAND studies are published in peer-reviewed scholarly journals, as chapters in commercial books, or as documents published by other organizations.

Our mission to help improve policy and decisionmaking through research and analysis is enabled through our core values of quality and objectivity and our unwavering commitment to the highest level of integrity and ethical behavior. To help ensure our research and analysis are rigorous, objective, and nonpartisan, we subject our research publications to a robust and exacting quality-assurance process; avoid both the appearance and reality of financial and other conflicts of interest through staff training, project screening, and a policy of mandatory disclosure; and pursue transparency in our research engagements through our commitment to the open publication of our research findings and recommendations, disclosure of the source of funding of published research, and policies to ensure intellectual independence. For more information, visit

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.