Thomas Holmes and Richard Rahe examined the medical records of over 5,000 medical patients as a way to determine whether stressful life events might cause illnesses.

Patients were asked to tally a list of 41 life events based on a relative score.

A positive 0.1 correlation was found between their life events and their illnesses. Thus, the Social Readjustment Rating Scale (SRRS) or the Holmes and Rahe Stress Scale was born. However, this study can be perceived as unreliable since it asks participants to look back at their life events, making the data retrospective.

Scale of Major

1. Score of 300+: At risk of illness.
2. Score of 150-299+: Risk of illness is moderate (reduced by 30% from the above risk).
3. Score 150-: Only have a slight risk of illness.

Scale of Minor

1. Score of 300+: At risk of illness.
2. Score of 150-299+: Risk of illness is moderate. (reduced by || 30% from the above risk)
3. Score 150-: Slight risk of illness.