The social readjustment rating scale (SRRS) was developed by Holmes and Rahe (1967), two medical doctors who noted a link between stressful live events and illness. In order to create a scale to measure this link, Holmes and Rahe constructed a list of stressful events and asked a sample of nearly 400 people to rate them in terms of their severity. Holmes and Rahe then took an average of each rating to form the SRRS (e.g. death of a spouse = 100, marriage = 50, fired from work = 47, son or daughter leaves home = 29 etc.). These numbers are known as life change units. When the scale is used in research, participants are asked to check off any of the 43 life events they have experienced over a given time period (e.g. 12 or 6 months). The scores are then totalled and used as an index for the amount of life stress the participant has experienced.