The learning analytics dashboard (LAD) is a newly developed learning support tool for virtual classrooms that is believed to allow students to review their online learning behavior patterns intuitively through the provision of visual information. The purpose of this study was to empirically validate the effects of LAD. An experimental study was conducted with a dashboard treatment group and a control group. The researchers developed a LAD and evaluated its effectiveness on the sample of 151 college students at a private university located in Korea, who were taking the online course titled "Management Statistics" in the first semester of 2014. The following results were obtained. First, the students who received dashboard treatment presented higher final score than those who did not. Second, the dashboard usage frequency, as measured by the number of times the dashboard was opened, did not have a significant impact on learning achievement. However, a slightly positive correlation between satisfaction with LAD and learning achievement was observed. Further analysis indicated that learners who used the dashboard only a few times showed relatively high satisfaction with LAD. On the other hand, high academic achievers who opened LAD relatively frequently showed lower satisfaction with dashboard. The results guide that LAD should be revised in a way to motivate learners consistently and support learners who have different academic achievement levels. The study discusses the further research tasks in terms of LAD development as an effective and personalized feedback tool to improve learners' academic achievement.