We investigated the effectiveness of reusable learning objects (RLOs) when delivered in a workshop or released for self-study with groups of student-nurses studying chemistry. Analysis of examination results showed that the proportion of students answering chemistry questions correctly increased significantly in both the workshop and self-study cohorts following the introduction of the RLOs. In terms of the factors that supported learning, students rated functional characteristics, such as universal availability and control over learning, as more important than media characteristics, such as audio-narration and interactivity. There was no correlation between ratings and the age of the respondent, their computer confidence or whether they studied alone or in the workshop. Similarly, design differences between individual RLOs did not appear to detract from learning. Data suggest that the sense of control and ownership of the learning process that RLOs afforded to the learners were the keys to their effectiveness. By reporting the attainment of study cohorts compared with non-intervention groups, exploring differential learning-contexts for RLO use and by providing empirical evidence of reuse, the study provides evidence which is underreported in the literature despite the wide uptake of learning object format.