SPSG #12: Personal Technique

This chapter is largely written in the first person, and it does so largely for the purpose of disparaging the concept of scientific objectivity. It starts out by describing how several reorganizations dramatically affected the branch at the USFDA that I worked in for 25 years. In the end, it was swallowed up by the shell game. It then goes on to discuss the importance of recognizing the subjective nature of science, particularly when the science is unsettled and uncertain. The objectivity facade is partly attributable to scientific writing style that takes the author out of discussions of factual issues, which hides tha fact that personal opnions are beign expressed.   To demonstrate what science is really like, I walk through the personal choices I made in developing the dose-response model for arsenic and lung cancer that was used for the apple juice and rice risk assessments discussed in Chapter 11. Some of those choices were done by committee and some were not, but either way they all involved subjective scientific judgements made in a fog of uncertainty. In one case, I made a different choice that I had previously because new information influenced my subjective judgment about how to go about estimating lifetime risks from a prospective epidemiological study, which underscores the notion that “objective” reality evolves with scientific inquiry. The resulting dose-response model is then used to provide risk estimates for someone with a high-end (for the United States) arsenic intake. In addition to providing the lifetime risk estimates that were also given in the FDA reports on apple juice and rice, estimated changes in average life expectancy are also provided. For the purpose of making an individual choice, the latter measure is far more meaningful. The chapter then suggests that the inability of EPA to provide a dose-response characterization for arsenic may stem from a wrongheaded demand for objectivity that dictates the use of the wrong probability and the wrong personnel for a job that needs statistical theory instead of statistical probability.