Using the standard error of measurement to identify important changes on the Asthma Quality of Life Questionnaire

Qual Life Res. 2002 Feb;11(1):1-7. doi: 10.1023/a:1014485627744.


Objectives: To establish a link between the minimal important difference (MID) and the standard error of measurement (SEM) for all responsive dimensions of the Asthma Quality of Life Questionnaire (AQLQ).

Methods: Secondary data analysis of baseline and follow-up interview data from 198 outpatients with asthma enrolled in a randomized controlled trial and receiving care at a major urban academic medical center's general medicine clinics. Domain statistics for baseline and follow-up interviews were examined for the AQLQ. The baseline SEM values were compared with established AQLQ MID standards using weighted kappa values.

Results: One SEM identified the MID in responsive AQLQ dimensions. Weighted kappa values (0.88-0.93) validated excellent agreement between these two criteria.

Conclusion: This is the third study to support using one SEM to identify important individual change in health-related quality of life (HRQoL) measures. However, refinement of the process for determining a measure's clinically meaningful differences is still needed to secure a link between the SEM and the identification of relevant HRQoL change over time.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Asthma / psychology*
  • Chronic Disease
  • Humans
  • Interviews as Topic
  • Quality of Life*
  • Reproducibility of Results
  • Statistics as Topic
  • Surveys and Questionnaires / standards*
  • Urban Population