You review a patient’s appointment attendance over the most recent 12-month period to get a better sense of their retention in care, with a specific interest in determining if this individual has had any ‘gaps in care’—a measure of retention that can be used as a surrogate for determining if a patient has been lost to follow-up. The chart below details the patient’s appointments attended (✔), as well as no-shows (✖).
 

	Quarter 1	Quarter 2	Quarter 3	Quarter 4
Patient One	✔	✖   ✖	✔   ✖	✔