The purpose of this study was to examine factors that may impact visual tracking tests (VTT) utilized to assess concussions. VTT add validity and reliability to the concussion protocol because they are physiologically based and not dependent upon cognitive responses and influences such as motivation to return to play. However, VTT are not without concern for accuracy and it is possible that several factors could influence results. In addition, the use of VTT as part of the concussion protocol has not been completely standardized. Two factors that stand out as possibly influencing results: time of day and the setting in which tests are conducted. If these factors are found to influence VTT results, they need to be taken into account and tightly controlled.