  The attributable risk, often called the population attributable risk, is in
many epidemiological contexts a more relevant measure of exposure-disease
association than the excess risk, relative risk, or odds ratio. When estimating
attributable risk with case-control data and a rare disease, we present a
simple correction to the standard approach making it essentially unbiased, and
also less noisy. As with analogous corrections given in Jewell (1986) for other
measures of association, the adjustment often won't make a substantial
difference unless the sample size is very small or point estimates are desired
within fine strata, but we discuss the possible utility for applications.
