2. Principles of Measurement Scales

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

Published Online: 8 MAR 2002

DOI: 10.1002/0470846283.ch2

Quality of Life: Assessment, Analysis and Interpretation

Quality of Life: Assessment, Analysis and Interpretation

How to Cite

Fayers, P. M. and Machin, D. (2000) Principles of Measurement Scales, in Quality of Life: Assessment, Analysis and Interpretation, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/0470846283.ch2

Author Information

  1. 1

    Medical Research Council Clinical Trials Unit, London, UK

  2. 2

    Unit of Applied Clinical Research, Norwegian University of Science and Technology, Trondheim, Norway

  3. 3

    NMRC Clinical Trials & Epidemiology Research Unit, Singapore

  4. 4

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

Publication History

  1. Published Online: 8 MAR 2002
  2. Published Print: 18 APR 2000

ISBN Information

Print ISBN: 9780471968610

Online ISBN: 9780470846285



  • constructs;
  • latent variables;
  • indicator variables;
  • causal variables;
  • global questions;
  • multi-item questionnaires;
  • multi-item scales;
  • psychometrics;
  • item response;
  • clinimetric scales


The principle methods for developing and validating new questionnaires are introduced, and the different approaches are described. These range from simple global questions to detailed psychometric and clinimetric methods. We review traditional psychometric techniques including summated scales and factor analysis models, as well as psychometric methods that place emphasis upon probabilistic item response models. Whereas psychometric methods lead to scales for QoL that are based upon items reflecting patients' level of QoL, the clinimetric approach makes use of composite scales that may include symptoms and side-effects of treatment.