A micro-level approach to the study of relationships between component processes within self-regulated learning in young adolescent students is described. Using this approach, contingencies between self-regulatory processes can be identified and insight into factors that promote students' use of self-regulatory strategies can be investigated. Evidence is presented showing how the influence of mastery achievement goals on specific task goals can be mediated by students' state of interest. Further development of this approach requires consideration of the measurement issues associated with using single items to measure on-task states. Evidence for the reliability and validity of single-item measurement of states is considered in relation to areas of psychological inquiry that regularly use single-item measures and we conclude that further development of these types of measure has the potential to expand our understanding of self-regulated learning.