A booklet of a programmed-instruction type was developed to obtain the measures needed to test Carroll's model of school learning, including ability, aptitude, quality of instruction, opportunity for learning, perserverance, and time criterion. Simple rules in an artificial foreign language were taught by means of the booklet to sixth-grade children. Poor quality instruction was found to retard the learning rate of children at all IQ levels, and to be almost as detrimental for children of higher intelligence as for children of lower intelligence. It also resulted in reduced perserverance among high IQ children but had no significant effect on the perserverance of children with IQ's of 115 or below. Statistics were developed to indicate the efficiency of learning under conditions of inadequate opportunity. The empirical data generally confirmed the trends hypothesized in Carroll's model. These findings, if confirmed in other studies, would emphasize the need for good teaching for the more able as well as the less able student. Learning was also shown to be highly inefficient when students had insufficient opportunity for learning. This suggests that learning efficiency measures should be established for children of different intelligence levels for given units of instruction. Such data would allow teachers to assess required amounts of learning time much more accurately than is possible at present. (Author)