Holmes and Rahe next took their list of life-changes to thousands of men and women in many walks of life in the United States and Japan. Each person was asked to rank order the specific items on the list according to how much impact each had. Which changes required a great deal of coping or adjustment? Which ones were relatively minor?

To Holmes' and Rahe's surprise, it turned out that there is widespread agreement among people as to which changes in their lives require major adaptations and which ones are comparatively unimportant. This agreement about the "impact-fullness" of various life events extends even across national and language barriers. (The work in the United States and Japan is now being supplemented by studies in France, Belgium and the Netherlands.) People tend to know and to agree on which changes hit the hardest.

Given this information, Holmes and Rahe were able to assign a numerical weight to each type of life change. Thus each item on their list was ranked by its magnitude and given a score accordingly. For example, if the death of one's spouse is rated as one hundred points, then moving to a new home is rated by most people as worth only twenty points, a vacation thirteen. (The death of a spouse, incidentally, is almost universally regarded as the single most impactful change that can befall a person in the normal course of his life.)

Now Holmes and Rahe were ready for the next step. Armed with their Life-Change Units Scale, they began to question people about the actual pattern of change in their lives. The scale made it possible to compare the "changefulness" of one person's life with that of another. By studying the amount of change in a person's life, could we learn anything about the influence of change itself on health?

To find out, Holmes, Rahe and other researchers compiled the "life change scores" of literally thousands of individuals and began the laborious task of comparing these with the medical histories of these same individuals. Never before had there been a way to correlate change and health. Never before had there been such detailed data on patterns of change in individual lives. And seldom were the results of an experiment less ambiguous. In the United States and Japan, among servicemen and civilians, among pregnant women and the families of leukemia victims, among college athletes and retirees, the same striking pattern was present: those with high life change scores were more likely than their fellows to be ill in the following year. For the first time, it was possible to show in dramatic form that the rate of change in a person's life – his pace of life – is closely tied to the state of his health.

"The results were so spectacular," says Dr. Holmes, "that at first we hesitated to publish them. We didn't release our initial findings until 1967."

Since then, the Life-Change Units Scale and the Life Changes Questionnaire have been applied to a wide variety of groups from unemployed blacks in Watts to naval officers at sea. In every case, the correlation between change and illness has held. It has been established that "alterations in life style" that require a great deal of adjustment and coping, correlate with illness – whether or not these changes are under the individual's own direct control, whether or not he sees them as undesirable. Furthermore, the higher the degree of life change, the higher the risk that subsequent illness will be severe. So strong is this evidence, that it is becoming possible, by studying life change scores, actually to predict levels of illness in various populations.

Thus in August, 1967, Commander Ransom J. Arthur, head of the United States Navy Medical Neuropsychiatric Research Unit at San Diego, and Richard Rahe, now a Captain in Commander Arthur's group, set out to forecast sickness patterns in a group of 3000 Navy men. Drs. Arthur and Rahe began by distributing a Life Changes Questionnaire to the sailors on three cruisers in San Diego harbor. The ships were about to depart and would be at sea for approximately six months each. During this time it would be possible to maintain exact medical records on each crew member. Could information about a man's life change pattern tell us in advance the likelihood of his falling ill during the voyage?

Each crew member was asked to tell what changes had occurred in his life during the year preceding the voyage. The questionnaire covered an extremely broad spectrum of topics. Thus it asked whether the man had experienced either more or less trouble with superiors during the twelve-month period. It asked about alterations in his eating and sleeping habits. It inquired about change in his circle of friends, his dress, his forms of recreation. It asked whether he had experienced any change in his social activities, in family get-togethers, in his financial condition. Had he been having more or less trouble with his in-laws? More or fewer arguments with his wife? Had he gained a child through birth or adoption? Had he suffered the death of his wife, a friend or relative?

The questionnaire went on to probe such issues as the number of times he had moved to a new home. Had he been in trouble with the law over traffic violations or other minor infractions? Had he spent a lot of time away from his wife as a result of job-related travel or marital difficulties? Had he changed jobs? Won awards or promotions? Had his living conditions changed as a consequence of home remodeling or the deterioration of his neighborhood? Had his wife started or stopped working? Had he taken out a loan or mortgage? How many times had he taken a vacation? Was there any major change in his relations with his parents as a result of death, divorce, remarriage, etc.?

In short, the questionnaire tried to get at the kind of life changes that are part of normal existence. It did not ask whether a change was regarded as "good" or "bad," simply whether or not it had occurred.

For six months, the three cruisers remained at sea. Just before they were scheduled to return, Arthur and Rahe flew new research teams out to join the ships. These teams proceeded to make a fine-tooth survey of the ships' medical records. Which men had been ill? What diseases had they reported? How many days had they been confined to sick bay?

When the last computer runs were completed, the linkage between changefulness and illness was nailed down more firmly than ever. Men in the upper ten percent of life change units – those who had had to adapt to the most change in the preceding year – turned out to suffer from one-and-a-half to two times as much illness as those in the bottom ten percent. Moreover, once again, the higher the life change score, the more severe the illness was likely to be. The study of life change patterns – of change as an environmental factor – contributed significantly to success in predicting the amount and severity of illness in widely varied populations.

"For the first time," says Dr. Arthur, appraising life change research, "we have an index of change. If you've had many changes in your life within a short time, this places a great challenge on your body ... An enormous number of changes within a short period might overwhelm its coping mechanisms.

"It is clear," he continues, "that there is a connection between the body's defenses and the demands for change that society imposes. We are in a continuous dynamic equilibrium ... Various 'noxious' elements, both internal and external, are always present, always seeking to explode into disease. For example, certain viruses live in the body and cause disease only when the defenses of the body wear down. There may well be generalized body defense systems that prove inadequate to cope with the flood of demands for change that come pulsing through the nervous and endocrine systems."

The stakes in life-change research are high, indeed, for not only illness, but death itself, may be linked to the severity of adaptational demands placed on the body. Thus a report by Arthur, Rahe, and a colleague, Dr. Joseph D. McKean, Jr., begins with a quotation from Somerset Maugham's literary autobiography, The Summing Up: