The validity of single-item, self-assessment questions as measures of adult physical activity

J Clin Epidemiol. 1990;43(11):1123-9. doi: 10.1016/0895-4356(90)90013-f.


Individual energy expenditure (kcal/kg/day) was calculated from a detailed set of questions from the Health Promotion and Disease Prevention Supplement of the 1985 National Health Interview Survey. Responses to three single-item, self-assessment questions were compared to the energy expenditure variable to test criterion validity. Spearman's correlation coefficient revealed moderate correlations between energy expenditure and corresponding levels of self-assessed leisure-time physical activity for each single-item question (r = 0.14 to 0.41). For purposes of measuring prevalence of physical activity, the energy expenditure variable was used to categorize individuals into activity levels. The single-item questions were found to have Spearman's correlations with the categorical measures ranging from 0.11 to 0.37 for leisure-time activities. Generally higher correlations were found for males and younger age groups (18-34 years). The relationships were interpreted as being weak relative to an expected correlation of 0.75 for criterion validation. However, the single-item questions show promise for obtaining proxy estimates of the degree of leisure-time physical activity in a population.

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Energy Metabolism*
  • Exercise*
  • Female
  • Humans
  • Leisure Activities*
  • Male
  • Middle Aged
  • Reproducibility of Results
  • Sex Factors
  • Surveys and Questionnaires / standards*
  • Work / physiology*