Assessment of reliability of lung function screening programs or longitudinal studies

Am J Respir Crit Care Med. 1999 Dec;160(6):2006-11. doi: 10.1164/ajrccm.160.6.9902042.


The aim was to determine reliability of lung function measurements performed according to recommendations of the American Thoracic Society (ATS) at a screening program in a large South African gold mine and to determine the usefulness of the reliability coefficient G for monitoring the reliability of lung function measurements in a mass screening program. The reliability coefficient G estimates the amount of random error of measurement, relative to the total variation in a measurement. The coefficient G was calculated as a correlation coefficient between two consecutive lung function tests performed within 6 mo, over a period of 43 mo on 3,378 miners. There was significant temporal variability in the reliability. For FEV(1), the coefficient G showed increased variability over the first 5 mo and stabilized at a value of 0.93 for the next 23 mo, after which it systematically declined over the next 15 mo. We estimated that in a large screening program, an optimal sample size of around 900 miners, examined randomly throughout the year, on a yearly basis, would provide a sufficient sample to examine monthly or quarterly fluctuation in the reliability. The value of the reliability coefficient G did not change when the time between two consecutive tests increased up to 15 mo. In conclusion, monitoring of lung function reliability in a screening program by the reliability coefficient G should improve data quality, and provide a measure on which the confidence in a decision-making process could be based when examining temporal changes in lung function for individual subjects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Forced Expiratory Volume
  • Gold
  • Humans
  • Longitudinal Studies
  • Lung Diseases, Obstructive / diagnosis
  • Male
  • Mass Screening*
  • Mining
  • Occupational Diseases / diagnosis
  • Reproducibility of Results
  • Respiratory Function Tests*
  • Vital Capacity


  • Gold