Longoria's research uses personal control theory, which is similar to person in environment theory. According to Longoria (2009), “like previous person-environment theoretical frameworks of grandparents' emotional well-being, the conceptual model integrates the notion that caregiver affection is a function of available resources applied to the ongoing negotiation of the caregiver and caregiver role requests." This theory returns control to custodial grandparents by allowing them to explore the resources of their community. However, there are many limitations of the theory. The theory relies heavily on an individual's access to community resources, but does not take into account a person's ability to do so. If this theory were used as a social work intervention, it would be difficult to imagine a positive effect on the individual's well-being. In fact, Longoria states, “it is theorized that the degree to which grandparents perceive they can achieve a satisfactory level of personal control substantially influences their emotional capacity”.