No randomized control trials currently show the the impact of a medication wallet card/list on patient enablement. One study showed that a significant percentage of the patients were willing to use a self-maintained wallet-sized medication list. In addition, those who used the medication list showed an improved sense of knowledge about their medical problems and medication, and also exhibited an enhanced sense of responsibility in maintaining their medication lists. However, the study considered a relatively young population that only included patients over the age of 40 and did not stipulate a minimum number of medications for the patients to be taking. In addition, the study was not a randomized control trial, and used the Patient Medication Scale (PMS) to measure outcomes.