This study in the domain of statistics compares four information presentation formats in a 2 x 2 factorial design: timing of supportive information (before or during task practice) ? timing of procedural information (before or during task practice). Seventy-two psychology and education students (7 male and 65 female; mean age 18.5 years, SD = 2.85) participated. The effectiveness of the learning material was measured by test performance. The instructional efficiency was measured by a combination of mental effort during practice and test performance (i. e., a high test performance combined with a low mental effort during practice denotes a high instructional efficiency). ANOVA showed a main effect for timing of supportive information: presentation "during" practice led to more "efficient" learning than presentation "before" practice. Moreover, an interaction effect was found. Simultaneous presentation of procedural information "before" and supportive information "during" practice led to the most "efficient" learning.