“…Over the past few years, some techniques have been developed to increase follow‐up rates, including paying the patient with money (e.g., Davis, Estess, Simonton, & Gonda, 1977) or lottery tickets (Norman, McFarlane, Streiner, & Kneale, 1982), or having the person give a deposit that is refunded in part at each visit (e.g., Hagan, Foreyt, & Durham, 1976). Some studies have gone so far as to place ads in newspapers and hire private detectives to find subjects; through “heroic,” albeit expensive, means, one multicenter, multicountry study was able to trace all except 2 of its 1,377 subjects (EC/IC Bypass Study Group, 1985).…”