Perry and Winne (2006) describe their computer program, "gStudy", and argue that it facilitates valid measurement of self-regulated learning (SRL) over time. This commentary addresses the assumptions underlying this argument and raises additional validity questions regarding the use of this tool. These include issues related to the development of SRL in young children, the difficulty in embedding assessments in a learning tool, and the extent to which the log analyzer can separate SRL sequences from other behavior. Finally, the extent to which behavior "inside" gStudy reflects SRL in other contexts is discussed.