The Validity of Measuring Health,
Happiness and Longevity on Word Scales
a. Can we ask a "subjective" question like, "Would you describe your
overall level of health as excellent, very good, good, fair or poor" and expect it to
be a valid predictor of actual health?
Yes. A 1991 study by Idler and Kasl states, "Self-evaluations of health status have
been shown to predict mortality, above and beyond the contribution to prediction made by
indices based on the presence of health problems, physical disability, and biological or
life-style risk factors." The risk of mortality increases as the scale rating
decreases from excellent to poor.
The authors also cite five other recent studies that "…have found
self-evaluations of health to be significant predictors of mortality in follow-up studies,
despite stringent controls for physical health status at baseline. That is, above and
beyond several other different indicators of health, this subjective perception appears to
carry an independent ability to predict the individual's survival over a period of as many
as six to nine years. The answer to this apparently simple question thus communicates life
expectancy information, the sensitivity of which goes beyond the information contained in
detailed assessments of health problems and disabilities."
The authors raise an interesting possibility to explain some of their data,
"…that the perception of health status has some beneficial or detrimental effect
on the individual's subsequent experience of morbidity. In this case people who report
good health despite medical findings or, conversely, people whose health complaints are
apparently unjustified, may actually alter their risk of mortality by bringing their
health status into line with their self-perceptions." They say further research is
needed.
The authors raised another interesting issue of whether peoples' ratings on the health
scale are worse, the same or better at predicting mortality than physicians' evaluations.
"Health Perceptions and Survival: Do Global Evaluations of Health Status
Really Predict Mortality?" Ellen L. Idler and Stanislav Kasl, Journal of Gerontology:
SOCIAL SCIENCES, Vol. 46, No. 2, S55-65
b. Is it possible that the "subjective" rating by people on the health scale is
a better predictor of actual health than the evaluation of physicians using
"objective" data?
Yes. A 1999 study by Ferraro and Farmer states, "This study compares self-reported
morbidity with indicators of morbidity from physicians' evaluations and examines the
predictive validity of each indicator on self-assessed health and mortality in adulthood.
Special attention is given to differences in the measures between white and African
American adults. Adults from a large national survey received a detailed medical
examination by a physician; they also were asked about the presence of 36 health
conditions." The respondents' records were studied after a twenty year period.
"…This research evaluated the utility of morbidity data reported by respondents
with that provided by physicians for predicting health assessments and mortality. The two
types of morbidity were only modestly correlated. All four indicators of morbidity-two
reflecting physician-evaluated morbidity and two reflecting self-reported morbidity-were
predictive of self-assessed health among white respondents. The relationships between
self-assessed health and the two indicators of self-reported morbidity, however, were
stronger than were those with physician-evaluated morbidity in the white
subsample. For
the black subsample, neither indicator of physician-evaluated morbidity was significant in
predicting self-assessed health, but both indicators of self-reported morbidity were
significant. In summary, self-reported morbidity is the stronger predictor of
self-assessed health among all respondents, and physician-evaluated morbidity is
predictive of health assessments only among white respondents."
"It is not surprising that self-reported morbidity is the stronger predictor of
self-assessed health, given that the outcome was a subjective appraisal of health. Yet,
even when mortality is the outcome, physician-evaluated morbidity was not the superior
predictor…."
Ferraro & Farmer, “Utility of Health Data from Social Surveys: Is There a
Gold Standard for Measuring Morbidity?” American Sociological Review
(1999)
c. In our Good Samaritans International research we have found that the excellent to poor
health scale can predict differences in health between groups. Using large samples
(n=750/group), a telephone questionnaire, and the question, "Would you say your
overall level of health is excellent, very good, good, fair or poor?" we studied
three groups, each with a different incidence of the same disease.
Group 1 had Disease A and the group was identified because all respondents were taking
specific prescription drugs for the disease. Group 2 claimed to have Disease A but it was
suspected from past research that about half of the people actually had what was claimed
while the other half claimed to have the disease just to get unspecified free and
discounted items. Group 3 was considered to be a normal group in that it should have had
Disease A in proportion to the population as a whole, estimated to be 5%-10%.
From interviewing the people in the three groups the incidences of excellent or very good
claimed health follows.
Group 1 Diseased 33%
Group 2 Half Diseased 49%
Group 3 Normal 66%
d. We conclude that claimed health on the overall health scale is a good predictor of
actual health and even better than physicians' evaluations. But then why shouldn't we know
more about ourselves than anyone else?
A change in claimed health on the scale is predictive of an actual change in health and
when negative this is probably what causes us to go to the doctor. On the other hand when
we experience no change on our overall health scale and we go to the doctor for a physical
and he/she finds a change, maybe it is not as predictive of our actual health and
morbidity as our internal scale. How many people have had a physical which has led to
invasive heart procedures and now researchers are finding that the people refusing the
procedures are fairing as well as those having the procedures, or those with the traumatic
procedures fair no better than those refusing.
One of the most interesting issues raised is whether you can choose to move yourself up
the health scale and cause your actual health to improve. We don't see why this is not
possible. Becoming more positive and optimistic may create an internal environment and
seek an external environment conducive and supportive of better health, happiness and
longer life.
We, Good Samaritans, will research all of this to learn how to live better and help
others. |
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