A study of the reproducibility of the forced vital capacity of coalworkers at two collieries in Scotland and two collieries in South Wales.

A study of 1,522 coalworkers at two Scottish collieries and two Welsh collieries showed that the forced vital capacity (F.V.C.) was as reproducible a measurement as the forced expiratory volume (F.E.V.) (1 sec.). This applied not only to replicate readings, but also between readings taken before and after a working shift on the same day, and also between readings taken at an interval of one week. An examination of the results of F.E.V. (1 sec.) and F.V.C. readings taken on the entire colliery populations at a colliery in Ayrshire, Scotland, and one in South Wales showed that replicate readings of F.V.C. and F.E.V. (1 sec.) were equally reproducible and that reproducibility was virtually unaffected by the presence or absence of bronchitic symptoms or the different prevalence of pneumoconiosis at the two collieries.