I have read with interest the randomized clinical trial evaluating the effects of an adherence intervention for patients initiating human immunodeficiency virus (HIV) treatment by Gross and colleagues.1 This approach seems particularly useful for motivated patients who struggle with achieving or maintaining the high levels of adherence required for long-term viral suppression. Although well designed, there are several issues that I would like to raise. First, the dependent variable “adherence” is based on data collected with electronic monitors (EMs), which was fed back to intervention group participants during the study. Electronic monitors are not consistently used by everybody all the time, particularly not by patients treated for HIV in high-income countries, who tend to prefer more discrete pill containers.2,3 In our experience, discussing adherence reports with these patients frequently leads to the detection and correction of suboptimal device use. The reported intervention effect may therefore comprise both improved adherence and more accurate EM use. It would be valuable if the authors would report on how they assured equally accurate EM data in both treatment arms and add mediation analyses showing that the intervention effects on viral load are (fully) mediated by improvements in adherence (see, for example, de Bruin et al3).