BOOKS OF RtfiDIfGS - PAHO/WHO

Kllarman
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thi prospects of realizing such economn ¡ies are much more limited than in the manufacture
of goods. Moreover, when the size of a program increases, factor costs may rise. Finally,
ua the scopo of a program approaches the size of the total population ?t risk, the extra
coast of additional units of output increases when increasingly resitant grouap are
encountered. Conversely, it has been suggested that in the early phases of a progran unit
cast is likely to be higher than later on, since administratora learn by doing (14, p. 24)
Cost-Benefit Verau Cost-Effectivenss Analys
Although it is not so difficult to estimate the costs of programs, it is quite difficult to
formulate the contents and expected outcomes of programs. In my judgment this has
been the chief obstacle to the useful application of cost-benefit or cost-effectiveness
analysis in the health field.
Elsewhere 1 have listed the data required by the economist for valuing outcomes (46).
A clear statement of each type of outcome is necessary. Certain events, such as death,
disability, extra unemployment, and the use of health services must be entered on a
calendar, beginning with the base year, and assigned a duration. The data should extend
for a period as close to a person's lifetime as possible, with particular attention to the
possible recurrence of illness and its exacerbation.
This list of data requirements implies a degree of knowledge about the effects of
health services on the health of a population that is often lacking. The obstacles to the
attainment of such knowledge are many. Medicine is not an exact science, and physicians
may disagree among themselves and the same physician may disagree with his own past
findings. Field studies are complicated by what Morris (64) calls the iceberg
phenomenon: members of the designated control group, who are presumably normal,
may in fact have the disease under investigation in asymptomatic form. The possibility of
inducing iatrogenic disease means that only studies performed on normal populations in
the community, which are far more costly than studies of captive clinical populations,
can yield valid results (65).
A serious gap in existing data arises from the lack of longitudinal studies of
populations. Few investigators possess the requisite patience and dedication, or
experience the necessary career stability. The funding agencies, under conditions of
budgetary stringency, have even shorter time horizons. Although statistical manipulation
of existing cross-section and time-series data is a much cheaper and almost alwaya
available approach, it may not afford an adequate substitute in many instances, especially
when a high degree of correlation exists among the independent variables under scrutiny.
In 1965 I reported that only one study met the longitudinal data requirementa listed
above-Saslaw's study (66) on rheumatic fever. Unfortunately, the report on this study
was truncated in publication. Neenan's study of chest x-rays for tuberculosis (60),
conducted in 1964, concentrated on the short term, on the ground that a recovered
patient suffers no impairment of earnings while early detection alone does not alter the
long-term outlook. No evidence is adduced for these assumptions.
Acton (24) has recently completed a cost-benefit analysis of alternative programn for
reducing deaths from heart attacks. He considered five programa: an ambulance with
specially trained nonphysician personnel; a mobile coronary care unit with a physician; a
community triage center; a triage center combined with the ambulance; and a program to
screen, monitor, and pretreat the population. The largest net benefit, whether measured