AIDS Risk, Quantification, and Rhetoric

As the word is commonly understood, risk is intrinsically related to computing the probability of undesirable events, along with their degree of harm. This operation requires quantifying, measuring, and comparing the consequences of events. Knowledge about AIDS risk, its prevention, and the transmission of HIV is expressed in quantities of risk: that is, in probabilities of infection, low cell counts, developing opportunistic infections, and the like. From a broader perspective, quantification is an intrinsic feature of the biomedicalization process discussed by Clarke et al. (2003): the permanent monitoring of health status and the transformation of everyday life activities into risk factors require the quantitative treatment of life features that we very often perceive as highly idiosyncratic, personal, and even unique. Yet features we view as pertaining to the quality of our lives are made computable and treated in terms of magnitudes. How does this happen?

With respect to AIDS, there are quite a few epidemiological papers computing the exact amount of risk for every risk category and for every type of risk behavior, and quantitative evaluations of risk are present in many clinical reports. Statistical figures seem to present us with an objective image of risk, based on precise mathematical operations and free of any rhetorical elements. How is such an objectivity obtained? How can we assert with such certainty that “doing X” or “doing Y” has such and such a risk probability?