There are many different researches conducted into life changes and/or daily hassles.
Holmes & Rahe, two American doctors saw that the medical records showed that patients who got ill the most contained lots of life events prior to their illness. They decided to make a list of 43 life events after looking at the medical records of over 5000 patients. They needed some way to make a relationship between life changes and how many times they got ill. So they got 400 men and women to look at the list and rate the events on how much adjustment they would require. After all of them had been ranked they found that death of a spouse was ranked the highest, with minor violations of the law was ranked the lowest. Each event was give a numerical value depending on how much readjustment was needed. These were called Life Change Units (LCU). The life events were put in a scale with highest numerical value being 100 and the lowest being 11 LCUs. The Social Readjustment and Rating Scales (SRRS) was ready to test the idea that life changes were stressors and could cause illness as they needed readjustment.
A study that used the SRRS is the Rahe (1970) sailor study. Rahe aimed to investigate whether life changes caused illness. He did this by collecting 2500 male American sailors and giving them each the SRRS to complete. Over six months a detailed medical records were kept of each salior. Each sailor was given