Healthcare and Medicine Reference
The American College of Medicine's ACP Journal Club periodically
updates the glossary of these epidemiological and biostatistical terms.
Such various risks, rates, proportions, and ratios are presented across the
medical literature as point estimates (as seen in the study). The uncertainty
of these measurements is quantified by computing the confidence intervals
(CI), usually reported as ranges within those true values for the whole popu-
lation (community or patients) most probably are, that is, 95% CI or 99% CI.
126.96.36.199 Beyond Causality: Combining Frequencies,
Fractions, Risks, and Proportions
As we have seen, various rates and ratios may be treated separately, each
reflecting a particular problem such as relative risks measuring the strength of
causal associations or etiological (attributable) fractions (proportional hazards
in the domain of prognosis) or the attributable benefit increase to quantify the
specificity (one cause among other) of a particular factor as a presumed cause.
Also, as an example, various frequencies and fractions are combined to
evaluate the diagnostic considerations (see Section 3.2 of Chapter 3 regard-
ing the validity of diagnostic tests).
How can various frequencies, rates, and ratios help us in our health pro-
grams and medical care priorities determinations?
At various levels of prevention, choices must often be made between vari-
ous health programs. As Table 2.5 shows, incidence or prevalence frequencies
Table 2.5 Uses of Frequencies, Rates, Ratios or Proportions at Various Levels of
Prevention and Choices in Health Program Considerations
Level of prevention
fraction of risk
reached by the