This study was designed to determine if the hours during which students participated in electronics training had any influence on their learning efficiency and their ability to function effectively as students, and to identify those factors that contributed to diminished learning efficiency. The three shifts used for the experiment were the night shift, the evening shift and the day shift, and the subjects were 279 enlisted soldiers enrolled in Phase I of a Computer Technology Repair Course. It was concluded that the night shift may be expected to have a reduced level of performance in learning tasks, and that the afternoon and evening hours may be more conducive to increased performance than the traditional school day. It was suggested that total performance could be improved by assigning students to the shift that best matches their individual bio-rhythms. (GEB)