A broad literature base on the instructional effectiveness of intensive and semester-length courses often fails to find significant differences between the formats. Of those studies that do find differences, most suggest that intensive courses are superior. However, many of the studies are theoretically or methodologically flawed, and none examined crucial, long-term differences. This examination of student characteristics and instructional effectiveness in one matched pair of educational psychology classes found that, initially, students in the intensive version of the course performed significantly better than students in the semester-length course on posttests of content and questions tapping higher-order learning. The two groups of students did not differ significantly in their affinity for learning (need for cognition), age or GPA, suggesting the superior performance was the result of the intensive course format and not any pre-existing student characteristics. However, follow-up research duplicating the original study with the same participants three years later failed to find any significant difference between the two formats, suggesting that the initial superiority of the intensive format will fade if not maintained.