Sometime take a look back in the schedule for patients that no-showed on follow-ups and see what the office did to contract them again. Is there a group of charts somewhere going back years with forgotten & missed patients?
Another interest point was that handoff's were considered a contributing factor in 20% of cases. Multiple handoffs means multiple (and compounding) six sigma rates. The more steps there are the higher the sigma value must be of each step to maintain the same overall error rate. Thanks to Running a Hospital for the link to the article.