The paper describes the development and validation of a fully automated selection testing system: MICROPAT (MICROcomputerised Personnel Aptitude Tester). The system administers a battery of tests specifically designed to assess aptitude for pilot training. General field testing has proved both the software and hardware to be sufficiently rugged to stand up to repeated use by a broad range of men from the Services, and provided a means of developing and refining early versions of the test software. The initial validation trial, using a sample of U.K. Army Air Corps pilot trainees, has shown a substantial improvement in the prediction of success in training (R = 0.57) over the level obtained using the current selection procedure. A further validation study is now being carried out on Royal Navy pilot and observer cadets. The present paper outlines the ongoing series of studies which is being carried out to examine various aspects of the construct validity of the new MICROPAT tests and discusses a procedure for defining measures of performance on complex dynamic tasks through the statistical modelling of expert judgements. Cet article dkrit le dkveloppement et la validation d'un systkme de stlection par tests entierement automatist: MICROPAT (MICROcomputerised Personnel Aptitude Tester). I1 s'agit d'une batterie de tests spkialement choisis pour mesurer les aptitudes des pilotes i l'entrainement. La pratique du test a prouvk la fois que software et hardware pouvaient rksister a I'utilisation rkpktk par un grand nombre de sujets et permettaient I'extemion et le perfectionnement de versions anttrieures de tests informatisb. L'essai de validation initiale, sur un khantillon de pilotes de I'Armke de I'Air du Royaume Uni, a montrk la nette Requests for reprints should be sent to D. Bartram, Department of Psychology (Ergonomics Research Group), University of Hull. HU6 7RX, U.K. The work reported in this paper was carried out while the MICROPAT system was being developed under a research contract from the Army Personnel Research Establishment. The opinions expressed in the paper are those of the author. and do not necessarily reflect the view of the M i n i s t r y of Defence. 'The MICROPAT system and tests are all Crown Copyright. The system hardware and software are available through the approved licences: Bartdale (Human