Criteria, such as the Screening Tool of Older Persons' Prescriptions (STOPP)/Screening Tool to Alert to Right Treatment (START) criteria, are tools used by clinicians to identify potentially inappropriate prescribing (PIM) and potential prescribing omissions (PPOs) among older adult patients. In this study, researchers evaluated three PIM/PPO criteria sets and found that all three performed poorly as diagnostic tools to identify inadequate drug treatment in older patients compared to counting the number of drugs on the patient’s medication list.