In higher education, many of the new teaching interventions are introduced in the format of audio-visual files distributed through the Internet. A pedagogical tool consisting of questions listed as learning objectives and answers presented using online videos was designed as a supplement for a molecular biology course and made available to a large class of upper-level undergraduate students. The aim of the current study was to evaluate the impact of online videos on test scores. For this, linear mixed-effect models were fitted to the data and used to jointly estimate the effect on exam scores of video access and a set other variables including gender, academic year, course segment and cumulative grade point average (CGPA) of students. On average, scores for the segment of the course corresponding to the introduction of the online videos increased by 2%. Interestingly, students with lower CGPAs benefited the most from access to online videos; if CGPA = 4.0/10, then average score increase was 6.2%. For students with a higher CGPA of 8.0/10.0, the average increase of scores was 1.0%. The measure of exam performance represents a preliminary evaluation of the educational intervention described. Overall, the availability of videos demonstrating the application of concepts to solve problems in molecular biology was associated with statistically significantly higher scores on the exams. (Contains 3 tables and 6 figures.)