Chapter 2. Principles of Measurement Scales

  1. Peter M. Fayers1,2 and
  2. David Machin3,4,5

Published Online: 27 APR 2007

DOI: 10.1002/9780470024522.ch2

Quality of Life: The Assessment, Analysis and Interpretation of Patient-Reported Outcomes, Second edition

Quality of Life: The Assessment, Analysis and Interpretation of Patient-Reported Outcomes, Second edition

How to Cite

Fayers, P. M. and Machin, D. (2007) Principles of Measurement Scales, in Quality of Life: The Assessment, Analysis and Interpretation of Patient-Reported Outcomes, Second edition, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9780470024522.ch2

Author Information

  1. 1

    University of Aberdeen Medical School, Scotland, UK

  2. 2

    Norwegian University of Science and Technology (NTNU), Trondheim, Norway

  3. 3

    Division of Clinical Trials and Epidemiological Sciences, National Cancer Centre, Singapore

  4. 4

    School of Health and Related Research, University of Sheffield, England

  5. 5

    United Kingdom Children's Cancer Study Group (UKCCSG), University of Leicester, England

Publication History

  1. Published Online: 27 APR 2007
  2. Published Print: 2 MAR 2007

ISBN Information

Print ISBN: 9780470024508

Online ISBN: 9780470024522

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Keywords:

  • measurement scale principles;
  • QoL issues - constructs, latent traits or factors;
  • QoL – multidimensional in nature;
  • causal indicator and effect indicator in structural equation modelling;
  • single-item versus multi-item scales;
  • visual analogue scales (VAS);
  • Cronbach's reliability coefficient for multi-item scales;
  • traditional psychometrics based on summated scales;
  • item response theory (IRT)

Summary

This chapter contains sections titled:

  • Introduction

  • Scales and items

  • Constructs and latent variables

  • Indicator variables and causal variables

  • Single global questions versus multi-item scales

  • Single-item versus multi-item scales

  • Psychometrics and item response theory

  • Psychometric versus clinimetric scales

  • Sufficient causes and necessary causes

  • Discriminative, evaluative and predictive instruments

  • Measuring quality of life: indicator or causal items?

  • Conclusions