Several demonstration programs were used in training older workers in four member countries of the Organisation for Economic Co-operation and Development. The Austrian program was a stonemasonry course for persons aged 18 to 55, one group using traditional methods and the other, the discovery (discrimination learning) method. In the United Kingdom, a study of 83 former steam locomotive engineers being retrained for Diesel-electric locomotives compared the two methods and the performance of younger (ages 29-30) and older (40-62) trainees. In the Swedish study, 22 subjects aged 18-29 and 23 aged 40-56 were trained in reading and interpretation of engineering drawings; traditional, Compendium (with programed instruction books), and discovery methods were compared. The United States project trained 242 subjects, aged 23-65, in separate 26-week courses in electrical work, data processing, and machine shop work, with each skill area divided between traditional and discovery methods. Overall findings seemed to indicate that the discovery method is useful if tuned to a given group and that, with appropriate training, a higher than usual training age gives no serious disadvantage. (ly)