Standardizing spirometry: problems and prospects.

Pulmonary function tests, as well as clinical tests of other physiologic functions, have been adopted from the clinical setting for use in epidemiologic studies. Because these tests require an individual's maximal effort, they present a challenge to conventional standards of measurement validity. The author demonstrates that attempts to standardize spirometry in current epidemiologic studies reveal a bias that causes underestimation of adverse pulmonary effects of occupational hazards.