Rahe et al (1970) procedure - gave adapted from of SRRS known as Schedule of Recent Experiences (SRE) to 2664 navy personnel serving aboard 3 US navy cruisers. Men asked to complete SRE for events they've experienced in past 6 months. SRE adapted to be more specific to military experiences and then produced their LCU score. During 6-8 month tour of duty, record kept anytime a man visited sick bay, as well as type and severity of illness, producing illness score. Neither participants nor medical staff aware of purpose of study, making it a prospective study