Part I of this study investigated possible variables determining "High Risk No Show" behavior on the part of patients in a dental clinic. Only "source of payment" seemed important; namely, that Medicaid patients were statistically more likely to be "High Risk No Show" patients (P less than .001). Race was associated but was found to be confounded with Medicaid. In an attempt to investigate the reasons for the Medicaid group being "High Risk No Show" patients, Part II of the study compared three distinct groups of patients at the Children's Hospital Medical Center Clinic. These included the self-paying group and the Medicaid group of the original sample of 90 in addition to the Union plan group (patients receiving free third-party payment care as an employee benefit). It was shown that both groups with third-party coverage were associated with "High Risk No Show" behavior. The type of "No Show" behavior, however, was different for the two groups. Union plan patients tended to cancel appointments or at least notify in advance of inability to keep an appointment. Medicaid patients, conversely, were just as likely to fail appointments and not file advance notice of inability to keep an appointment.